A 

Practical  Manual 

OF 

Steam  and  Hot-Water 
Heating 


By 
EDWARD  RICHMOND  PIERCE 


First  Edition 


DOMESTIC  ENGINEERING  COMPANY 

CHICAGO 

445    PLYMOUTH    COURT 
1911 


Copyright, 

DOMESTIC  ENGINEERING  Co. 
1911 


EDWARD   RICHMOND   PIERCE 


241333 


AUTHOR'S  PREFACE 


For  about  a  quarter  of  a  century  the  writer  of  these 
pages  has  been  connected  with  those  who  manufacture 
and  sell  boilers  and  radiators  for  steam  and  hot-water 
heating. 

During  this  long  period  it  has  been  his  daily  duty  and 
privilege  to  answer  the  questions  of  architects,  engi- 
neers, steam-fitters  and  house-owners  in  regard  to  every 
phase  of  the  house-heating  industry. 

To  do  this  with  some  degree  of  intelligence  on  his  own 
part,  and  to  keep  in  touch  with  the  remarkable  develop- 
ment of  the  science  of  heating  through  the  efforts  of 
heating  engineers  during  this  period,  has  compelled  him 
to ;  utilize  every  resource  at  his  command  and  become  a 
student  of  every  phase  of  this  somewhat  complex  subject. 

His  duties  have  compelled  him  to  visit  frequently  every 
section  of  our  country  and  to  become  acquainted  with 
the  heating  requirements  of  each.  Many  times  during 
these  years  he  has  been  urged  by  friends  to  give  some 
presentation  of  heating  principles  in  book-form. 

Experience  has  shown  that  in  every  doubtful  problem, 
it  was  because  some  involved  fundamental  principle  had 
not  been  fully  understood.  It  has  also  demonstrated 
that  the  majority  of  those  who  do  the  practical  work 
of  measuring  the  buildings  and  erecting  house-heating 
systems  of  steam  or  hot  water  require  that  the  informa- 
tion they  desire  be  given  in  simple  terms  of  ordinary 
conversation,  and  not  in  scientific  terms. 

In  the  present  work  I  have  endeavored  to  bring  out 
every  fundamental  principle  involved  in  the  science  of 
heating  in  a  manner  to  meet  that  need. 

To  a  great  number  of  authors  who  have  preceded  me 
"I  am  indebted.  There  is  scarcely  a  book  published  on  the 
subject  to  whose  author  thanks  are  not  due  for  some 
suggestion  or  fact.  The  list  is  too  long  for  specific 
mention.  To  each,  therefore,  who  in  a  way  is  quoted 
but  is  not  given  specific  credit  in  the  text,  I  now  tender 
my  thanks. 

The  agency  system  of  sale  that  prevailed  until  within 
a  few  'years  in  the  heating  industry,  left  as  a  legacy  to 

I 


those  who  must  carry  on  the  work  of  today  questions  for 
the  manufacturer  to  solve  as  momentous  as  those  that 
confront  the  architect,  engineer  and  steam-fitter.  The 
purport  of  these  questions  and  the  aid  that  the  archi- 
tect, the  engineer,  and  those  that  carry  out  their  plans 
can  give  to  the  heating  industry  by  a  more  complete 
knowledge  of  the  fundamental  principles  of  the  science, 
I  have  endeavored  to  make  evident.  When  these  factors 
have  each  a  personal  acquaintance  with  the  principles 
which  underlie  the  sciences  of  heating  and  ventilation, 
these  contributors  to  public  health  and  comfort  will  take 
their  rightful  position  as  among  the  greatest  of  practical 
sciences. 

Though  this  book  is  written  primarily  for  the  every- 
day workman  in  the  heating  industry  and  therefore  is 
without  the  usual  formulas  and  scientific  phrases,  it  is 
hoped  that  this  simplicity  of  treatment  will  not  prejudice 
the  more  technical  student  unfavorably.  Many  things  are 
carefully  explained  herein  for  the  first  time,  it  is  believed, 
in  the  history  of  heating  literature. 

October,  1911. 


ii 


PUBLISHER'S  PREFACE 


In  introducing  this  book  to  those  interested  in  the  heat- 
ing industry,  we  have  the  satisfaction  to  know  that  we 
are  offering  to  them  a  work  unique  in  its  construction 
and  invaluable  in  its  comprehensiveness  of  treatment. 
The  opportunity  of  securing  the  service  of  a  man  as  well 
fitted  as  Mr.  Pierce  to  deal  with  the  subject-matter  is 
extremely  rare.  He  was  equipped  for  the  task  by  years 
of  acquaintance  with  all  the  ramifications  of  the  heating- 
industry  and  because  he  has  seen  its  evolution  since  its 
beginning.  His  intimate  relations  with  users  of  the  prod- 
ucts throughout  the  country,  his  possession  of  practical 
and  technical  understanding,  breadth  of  judgment  and 
sympathetic  interest,  have  given  a  personal  element  to 
his  writings  not  to  be  found  so  distinctly  in  any  other 
book  on  heating  subjects. 

For  the  past  25  years,  Edward  Richmond  Pierce  has 
been  prominently  identified  with  the  heating  industry.  He 
commenced  as  a  manufacturer  of  heating  boilers  and 
wrought-iron  radiators  in  Maine.  He  next  became  the 
manager  of  the  eastern  branch  of  the  Michigan  Radiator 
&  Mfg.  Co.,  Detroit,  Mich.,  with  headquarters  at  Boston, 
Mass.  Upon  the  formation  of  the  American  Radiator 
Co.,  he  was  appointed  branch  manager  for  New  England 
and  the  Maritime  Provinces.  In  a  few  years  he  was 
transferred  to  the  middle  western  territory,  with  head- 
quarters at  Chicago.  Later,  this  territory  was  enlarged 
to  include  most  of  the  southern  states  east  of  the  Missis- 
sippi River,  the  seat  of  direction  being  Detroit.  With 
the  opening  of  the  Cincinnati  branch  of  the  American  Ra- 
diator Co.,  the  management  of  this  was  given  to  Mr. 
Pierce,  with  offices  in  that  city.  After  resigning  from 
this  position,  he  spent  some  time  on  the  Pacific  Coast. 
In  this  manner,  the  reader  will  understand  how  great 
have  been  his  opportunities  to  study  heating  conditions 
in  varied  climates  and  at  various  altitudes,  with  many 
different  fuels.  In  each  of  the  positions  held  by  him,  he 
has  been  consulted  constantly  by  the  leading  engineers 
and  architects  of  that  territory. 

The  appearance  of  "A  Practical  Manual  of  Steam  and 

III 


Hot- Water  Heating"  in  serial  form  has  aroused  wide  in- 
terest, not  only  among  the  users  of  heating  apparatus 
but  among  the  manufacturers  themselves.  Many  of  the 
leading  manufacturers  in  the  country  are  as  anxious  to 
secure  an  accurate  definite  basis  of  boiler-ratings  as  are 
the  steam-fitters.  But  this  will  never  be  accomplished 
with  the  same  degree  of  thoroughness  as  if  it  is  brought 
about  by  the  insistence  of  the  steam-fitters  themselves. 
It  is  to  stimulate  this  desire  that  this  manual  is  pub- 
lished. At  the  risk  of  being  accused  sometimes  of  repeti- 
tion, the  author  has  patiently  drilled  through  every  prob- 
lem ordinarily  met  with  in  estimating  and  installing  heat- 
ing apparatus,  under  varying  conditions.  It  has  been 
done  in  the  simplest  language,  so  that  there  may  be  the 
least  possible  chance  of  misunderstanding.  It  has  been 
well  done,  and  will  lay  a  foundation  for  the  building-up 
of  stable  heating  conditions  throughout  the  United  States. 


IV 


TABLE  OF  CONTENTS: 


Author's  Preface    x 

Publishers'    Preface    xii 

Section  I. 

Purpose  of  this   Book 1 

What    Constitutes   a  proper   Chimney 3 

How    Chimney-Draft   is    Measured 4 

The   proper  Area  for   Chimney- Flues 6 

Section  II. 

Chimney-Troubles     9 

Why  a  Suitable  Chimney  for  a  Hot-Air  Furnace  may 

not  be  Suitable  for  a  Steam  or  Hot- Water  Heater  11 

Heat  Loss  from  Buildings 14 

Section  III. 

Measuring   Buildings    for    Heat-Losses 17 

Form  for  Tabulating  Measurements 20 

Excessive  Heat-Loss  from  Wet  Brick  and  Other  Walls  21 

Section  IV. 

Details  to  be  Gathered  when  Building  is  Measured  for 

Heating  by   Steam    or    Hot-Water 26 

Common   Defect  in   Many  Rules 27 

Temperature  of  Steam  at  Various  Altitudes 29 

Effect  of  Altitudes  on  Required  Radiating  Surface....  30 

Section  V. 

The  Heat-Unit  and  Its  Relation  to  the  Heating  Prob- 
lem       35 

The  Values  or  Qualities  of  Heat 37 

Measurement   of  Heat    37 

Specific  Heat   38 

Latent  Heat   38 

Relation  of  Latent  Heat  to  House-Heating  by  Steam.  39 

Relation  of  Pressure  to  Sensible  Heat 39 

Heat-Units   from   Cast-Iron   Radiator  Surface  at  Vari- 
ous  Pressures    40 

V 


Section  VI. 

Illustration  of  Effect  of  Altitude  on  Quantity  of  Radi- 
ating Surface  Required 43 

The  Specific  Heat  of  Walls 44 

Heat  Required  to  Offset  the  Specific  Heat  of  Walls 
and  Other  Building  Material 45 

Arbitrary  Additions  Required  by  the  German  Govern- 
ment    48 

Section  VII. 

Loss  of  Heat  from  Building  Material  of  Various  Kinds  51 

Loss  of  Heat  through   Glass 52 

Why  German  Government  Requires  a  Different  Factor 
for  Heat-Loss  through  Glass  from  that  Found  by 

Scientists     53 

Effect  of  Wind    .....! 54 

The   Prevailing  Winds  of  the  United  States   56 

The  Force  of  Wind  in  Pounds  Pressure 57 

The   Velocity    of   Winter- Winds , 58 

Section  VIII. 

Loss  of  Heat  from  Wall?  from  Varying  Velocities  of 

Wind , .    59 

Loss  of  Heat  from  Windows  from  Varying  Velocities 

of   Wind    . . .  ! 60 

Loss   of  Heat  from   Doors 62 

Loss  of  Heat  from  Fireplace-Openings 64 

Loss  of  Heat  from  Minor  Sources 64 

Section  IX. 

Air  Discharged  from   Fireplace-Openings 66 

Incorrect  Use  of  Rules  for  Figuring  Radiating  Surface  69 
Loss  of  Heat  from   Floors 72 

Section  X. 

Loss  of  Heat  through  Partition-Walls 74 

Manner  of  Using  Heat-Losses  in  Figuring  for  Radi- 
ating Surface  75 

Section  XI. 

Radiation  of  Heat  from  Various  Formrs  of  Radiators..  80 

Sizing   Direct    Radiators 82 

Sizing    Indirect    Radiators 83 

Changes  in  Ratio  that  have  Occurred  in  Heating  Prac- 
tice between  Direct  and  Indirect-Radiating  Sur- 
face .  .  . ". 86 

VI 


Section  XII. 

Value  of  Indirect  Radiators  in  B.  t.  u 87 

The    Direct-Indirect    Radiator 92 

Section  XIII. 

Summary  of   Previous   Sections 95 

Rules  for  Ascertaining  Heat-Losses 97 

Condensed    Rule    for    Direct-Radiator    Surface    when 

Steam  at  Boiler  has  Pressure  of  2  Ib . .'  98 

Condensed   Rule   for   Direct-Radiator   Heating  Surface 

with  Other  Pressures  at  the  Boiler 98 

Condensed  Rule  for  Direct-Indirect  and  Indirect  Sur- 
face        99 

How  to  Determine  what  Pressure  a  Stated  Amount  of 
Radiating  Surface  in  a  Room  will  Require 100 

Section  XIV. 

Remarks    on    Piping   a    House 102 

Various   Systems  of  Piping 102 

Illustrating  Relation  of  Piping  to  Water-Line  of  Boiler.  103 
Piping  Incorrectly  the  Cause  of  Unsteady  Water- Line.  105 
Remedy  for  Most  of  the  Unsteady  Water-Lines  found 

in    House-Heating    Jobs 109 

A  Condensed  Study  of  the  Water- Line  Question Ill 

Section  XV. 

Piping  for  Steam  a  Development  of  a  Natural  Law..  113 

Loss  of  Pressure  in  a  Line  of  Piping 114 

Friction  in  Piping 115 

Getting  the  Water  of  Condensation  Back  into  Boiler.. 115 
Different  Pipe  Sizing  on  a  Small  House-Job 116 

Section  XVI. 

How  to  Figure   Pipe-Sizes  for  Different  Velocities  of 

Steam    118 

Standard  Length  of  Pipe  for  Determining  Velocity.  .  .122 
How  to  Figure  for  Velocity 123 

Section  XVII. 

Frictions   Caused  by  Fittings 125 

Steam-Delivery  Retarded  by  Friction  of  Fittings 126 

A  Fairly  Accurate  Guide  for  Sizing  Pipe  for  Heating..  128 

Section  XVIII. 

Piping  for  Overhead  Steam-Circuit 131 

Use   of  Ordinary   Fittings 134 

Friction  Increase  Caused  by  Fittings 135 

VII 


Section   XIX. 

Nine   Published    Pipe-Rules   Compared 141 

Showing  that  a  3-in.  Main  may  be  Correct  for  Either 
700  or  1900  Sq.  Ft.  Steam-Radiator  Surface  on 

Same  Job    143 

Wide  Variations  in  Piping  Rules  may  be  Reconciled.  .145 

Section  XX. 

Short  History  of  Steam-Heating  in  the  United  States.  148 

The  Piping  Plans  of  Thirty  Authorities  Analyzed 151 

The  Danger  of  Ready-Made  Piping-Rules 154 

Section  XXI. 

Selecting    a    Heating-Boiler 159 

Section  XXII. 

Power-Boiler   Ratings    166 

Horse- Power   Defined    166 

The  Unit  of  Power  Accepted  in  U.  S.  as  Standard 169 

The   Unit   of   Evaporation 169 

The  Measure  of  Capacity  of  Power-Boilers 171 

Comparison  of  the  2-lb.  Pressure  Rating  of  House- 
Heating  Boilers  and  the  Power-Boiler  Standard 
Rating 171 

Section  XXIII. 

Translating  Power-Boiler  Values  Into  Present  House- 
Heating  Practice  173 

House-Heating  Boiler  H.  P.  Shown  by  Radiating  Sur- 
face Carried  176 

Manufacturers'  Basis  for  Rating  House-Heating  Boil- 
ers   178 

Point  of  Greatest  Fuel-Economy 179 

Difference  Between  Power-Boiler  and  House-Heating- 
Boiler  Requirements  179 

Section  XXIV. 

Heating-Boiler  Catalogs  Lacking  in  Definite  Informa- 
tion   180 

Rate  of  Combustion  and  Evaporating  Power 184 

Section   XXV. 

Differences    in    House-Heating   Boiler-Ratings 187 

Stack-Temperatures    for    House-Heating    Boilers 187 

Six  Conservative   Ratings   Possible   on   Same   Boiler...  188 
Relation  of  Hours'   Run  to   Boiler-Rating 190 

VIII 


Relation  of  Radiator-Condensation  to  Boiler-Capacity.  191 

Correctness  of  Present  House-Boiler  Ratings 192 

Things   of    Importance   that   the    Purchaser   of   House- 
Heating  Boilers  Cannot  Now  Find  in   Catalogs.  .  .192 
An  Illustration  from  Four  Different   Boilers 192 

Section  XXVI. 

The   Burden  of  Selection  and  Garantee  Thrown  upon 

the    Engineer   by    Manufacturers 194 

Condensed   History   of   Cast-Iron    Heating   Boilers. ..  .196 
The  Slight  Change  in  Construction  since  First  Type..  196 

Brayton's    Boiler    197 

Exeter    Sectional    Boiler 198 

Section  XXVII. 

History    of    Cast-Iron    House-Heating    Boilers     Con- 
tinued      200 

Samuel   Gold's    Boiler 200 

The  First  Practical  Steam-Heating  Apparatus 204 

The  Improved  Gold's  System  of  Steam-Heating 207 

The  First  Mills'   Boiler - 207 

Cast-Iron   Boilers  as  Used  for  High-Pressure 208 

The    Harrison    Boiler 209 

Section  XXVIII. 

Information  that  the   Engineer  should  Possess  in  Re- 
gard   to    Heating   Boilers 211 

The    First    Thing   to    Find    Regarding    House-Heating 

Boilers     212 

Different  Weights  of  a  Cubic  Foot  of  Coal 213 

Relation   of   Coal   and    Cubic    Contents   of   Fire-Pot   to 

Hours'  Fire  is  to  be  Maintained 214 

Heating  Surface   in   House-Heating   Boilers 215 

One     Reason    for    Proper    Information    not    being    in 
Catalogs     215 

Section  XXIX. 

Things   Usually   Required  for   Power   Boilers  but   Not 

Usual  for  House-Heating  Boilers 218 

The  Different  Demand  on  Power-Boilers 219 

Difference    Between    Total    Capacity   and    Hourly    Ca- 
pacity      220 

Difference  in   Fire-Pot  Size  for  Various   Coals 220 

The  Combustible  in  Coal 221 

Classification    of    Coal    223 

Fire-Pot   Size   Needed  to   Furnish   Steam   Eight  Hours 
One  Firing  with   Hard  Coal 224 

IX 


I 


Section   XXX. 

Size  Fire-Pot  Needed  to  Furnish  Steam   Eight  Hours 

with  One  Firing  of  Soft  Coal 227 

Composition   of  Soot 229 

Relation  of  Bituminous  and  Semi-Bituminous  Coals  to 

Capacity   of   Fire-Pot 230 

Necessity  for  Designer  of  Heating  System  to  Know  the     . 

Kind  of  Coal  that  is  to  be  Used  as  Fuel 231 

Combustible  and  Heating  Values  in  Coal 232 

Weight  of  Ash  in  Different  Sizes  of  Coal 233 

Section  XXXI. 

Grates    for    House-Heating    Boilers 235 

Standardizing  House-Heating  Boilers 235 

United  States  Geological  Survey  Tests 236 

University   of   Illinois    Tests 237 

Lack    of    Satisfactory    Methods    for    Testing    Heating 

Boilers     238 

When  Testing  Rules  for  Power-Boilers  were  Prepared. 241 

Section  XXXII. 

Things  a  Testing  Code  Should  Develop 243 

Point  of  Greatest  Economy  in  Stack-Temperature. ..  .244 
Seven    Ratings    from    One    Size    Boiler-Grate    at    Dif- 
ferent   Stack-Temperatures    244 

Showing  How  Each  of  these  Ratings  may  be  Correct. 245 

Relation  of  Chimney  to  Stack-Temperature 246 

Fire  and  Heating  Surfaces  in  House-Heating  Boilers. 247 

Section  XXXIII. 

Direct   and   Flue-Surface   Values 249 

Description  of  a  Particular  Case 250 

Architects  and  Engineers  Should  Specify  Proportion 
of  Direct  and  Indirect  Fire-Surface  that  the  Heat- 
ing-Boiler Shall  Contain 251 

Some    Reasons   Why    Basis   of   Rating   House-Heating 

Boilers  is  not  Known 253 

A  Practical  Base  from  which  to  Make  Calculations  as 
to  the  Probable  Value  of  Heating  Surfaces 255 

Section  XXXIV. 

Well-Known  Authorities  Quoted  on  Heating  Surfaces. 257 
Transmission    of    Heat    through    Iron    to    Water    and 

through    Iron   to    Air 260 

Approximate  Temperature  of  the  Gases  when  Cast- 
iron  Boilers  are  Tested 261 

X 


Application   of   a   General   Law   of   Heat-Transmission 

to    Cast-iron    Boilers 261 

Experiment  with  Boiler  A 262 

Ratio  of  Heat  between  Direct  and  Indirect  or  Flue 
Surfaces  263 

Section  XXXV. 

Experiment  with  Boiler  A  Continued 264 

Experiment   with    Boiler   B 266 

Comparison  of  Two  Boilers  with  same  Amount  of 
Rated  Heating  Surface  but  Arranged  Differently. 269 

Section  XXXVI. 

General  Remarks  on  Hot- Water  Heating 271 

The  Beginning  of  Steam-Heating  in  the  United  States. 273 

First  Official  Report  of  Hot- Water  Heating 274 

Antiquity    of    Hot- Water    Heating 275 

The    Slight    Progress    Made    in    Hot-Water    Heating 

Methods  over  those  of  the  Ancients 276 

Present  Steam-Heating  Practice  Requires  Less  Pres- 
sure at  Crown-Sheet  of  Boiler  than  is  Developed 
in  Hot- Water  Heating  Boilers 277 

Section  XXXVII. 

Heating  Apparatus  not  Necessarily  a  Failure  because 

belonging  to   any  one   System ....279 

Suitable   Chimney  for   Hot- Water  Heaters 281 

Volume  of  Air  to  be  Delivered  to  Hot- Water  Heaters. 282 
Essentials  of  Selection  of  Steam  and  Hot-Water  Boil- 
ers Compared  283 

Section  XXXVIII. 

Principles  Involved  in  Hot- Water  System  Circulation. 285 
What  Produces  the  Circulation 286 

Section  XXXIX. 

The    Incompressibility    of    Water 290 

The  Capacity  of  Water  to  Absorb  Heat 291 

Section  XL. 

The    Circulation-Question    Elaborated 294 

The  Question  of  the  Difference  of  Weight  in  Columns 

of    Water    296 

The  Statements  often  Made  in  Regard  to  Water-Cir- 
culation   298 

XI 


Section  XLI. 

A  Fair  Statement  Regarding  the  Circulation  of  Water 

in  Pipes  and  Boiler  of  a  Hot-Water  System 299 

The  Point  where  Difference  in  Weight  Counts 300 

Terrific  Force  Possible  to  Obtain  if  Pipes  are  Sealed. 303 
The  Prime   Cause  of  the   Circulation  in  a   Hot-Water 

System    303 

Velocity  of  Flow  in  Heating  Pipes 304 

Section  XLII. 

What  Gets  the  Water  into  the  Boiler  against  the  Static 
Head  in  Hot-Water  Heating 307 

The  Point  of  Equalized  Pressure  in  Hot- Water  Sys- 
tems   307 

Conditions  where  Small  Pipe  can  be  Used  in  Hot- 
Water  House-Heating  310 

Patented   Seals    312 

Section  XLIII. 

Piping  for  Hot- Water  Heating 314 

Speed    of   Circulation 315 

Use  of  Special  Fittings 316 

The  Great  Number  of  Pipe-Sizes  Possible  in  Hot- 
Water  Heating  Systems 316 

Section  XLIV. 

Piping  for  Expansion-Tank 321 

Position  of  Patent  Seal  Important 322 

Piping  for  Sealed  Systems 322 

Average    Loss    in    Temperature    of   Water   in    Passing 

through  the   Radiator 323 

The  Use  of  the  Two-Pipe  Circuit  System 324 

The  Use  of  the  Overhead-Circuit  System 324 

The  Use  of  the  Single-Main   Pipe   System 324 

Pressure  at  Point  where  Highest  Radiator  Stands. ..  .325 
Loss  of  Sales  Because  of  Mail-Order  Houses 327 

Section   XLV. 

Condensed  History  of  House-Heating  Radiators 329 

Method   of   Rating   Radiators 330 

Gun-barrels  used  as  Radiators 331 

Early  Types   of  Radiators 332 

First  Patented  Radiator 332 

Nason,  Walworth  and  other  Wrought-Iron  Radiators. 333 

Some  of  the  Tests  Given  out  by  Nason 334 

Early  Types  of  Present  Style  of  Radiators 335 

The    Bundy    Radiator 335 

Fixing  the  Standard  Height  of  Two-Column  Radiators. 336 
The  Commencement  of  Scientific  Heating 338 

XII 


SUBJECT  CONTENTS: 


Absorption  of  water  by  walls.   22 

Air- 
heating,  B.  t.  u.  required  for  91 
passing  through  flue,   table  94 
specific  heat  of 36 

Altitude- 
effect  of  27 

examples    43 

steam — temperature    29 

Anthracite  vs.   semi-bitumin- 
ous     230 

Ash  from  different  coals 234 


B 

Balloon    construction 51 

Barometer-pressure     56 

Boilers— 

Brayton,   first  cast-iron 196 

Brayton  tested   198 

capacity    160 

cast-iron,  early  history  of.. 200 

cast-iron   heating,    data 175 

comparison   between   three. 244 
conflict     between     cast-iron 

and  wrought-iron    197 

construction   of  two 264 

evaporative   action   in 255 

Gold's   sectional    201 

Harrison     204 

horizontal  sectional    163 

hot-water,  selection  of 326 

house-heating,    horse-power 

of    173 

house-heating  tests    237 

Mills'   improved   205 

Mills'  original  safety 203 

Mills'    twin   section 206 

pressure   71 

Boiler- 
ratings  70,  159,  181,  188,  250 

ratings  in  catalog 265 

round  sectional   165 

selection   of    159,   322 

selection,    essentials  of 162 

vertical  sectional   163 

water-temperature  in..  .260,  261 
wrought-iron  216 

Box-coil   radiation    332 


Brickwork,    weight   of 46 

British  thermal  unit — 

B.  t.  u 36 

required  for   heating  air...   91 
to  evaporate  one   pound  of 
water 169 


Capstones  10 

Cartoons — 

"Domestic         Engineering" 
Pilot-boat  to  the  Rescue. 222 
Steam-fitter's  Choice 143 

Cast-iron,   specific   heat  of...  36 

Catalog  ratings    182,  265 

Chimneys     3 

air-passage   66 

dimensions    6 

flue-sizes     13 

height    7 

importance  in  hot-water  in- 
stallation      281 

throat    65 

Circle- 
areas    10 

area-table    12 

Coal— 

bushel-values    220 

comparison  of   ....  230 

composition    of    223 

pounds   to   cu.   ft 214 

steaming  value   183 

Combustion    in    coal 221 

rate   of    184 

Concrete  water-absorption.  22,  23 

Construction   heat-loss    20 


Direct- 
heating  surface  vs.  flue  sur- 
face   268 

indirect,   figuring  for 93 

indirect   radiators    80 

indirect  rule   99 

radiation,    condensed   rule. .  98 
radiation,  rule  for  sizing...   82 

radiators    80 

radiators         at         different 

boiler-temperatures    82 

surface   in   bo»T  >rs 258 


XIII 


Door  — 
losses     ,      

,.   62 

loss-table 

64 

Double  -boarded     floor-loss.. 
Draft   

.  .    74 
.  .      3 

gage 

4 

poor    ...           

.  .   10 

strength  of   . 

.  .187 

Evaporation — 

action    in    boilers 255 

power  of  boiler 178 

unit   of    169 

Expansion-tank,    piping   for.. 321 


Factors    of    heat-loss 26 

Fire-box  construction    257 

Fireplace  heat-loss   64 

Fire-pot  capacity.  .  .186,   'ill,   219 

Fire  surface   192 

Fire-travel   and   heating   sur- 
face     245 

Firing1 — 

basis     160 

test 227 

Fittings — • 

estimating  friction   of 127 

friction  of    114 

friction  of,   equal  to  pipe...  145 

Flat-coil  radiation  332 

Floor — 

heat-loss    20 

loss  table   73 

Floors  over  cold  cellars 74 

Flue- 
construction    9 

surface  in  boilers 258 

surface     vs.     direct-heating 

surface    268 

Flues,   chimney   3 

Form  for  figuring  radiation. 18,  I1) 
Friction — 

in   pipe    316 

of   fittings    114,    137 

Fuel  coal,  pounds  to  cu.   ft.. 214 
Fuel  economy  in  power-boiler.  17$ 

Garantee,    steam-fitters'     194 

German    allowance    for    heat- 
loss   , 49 

Glass   surface   in   windows. 62.  6:5 

Grate   size 192 

Gravity  steam- job  300 


generators 312 

intensity     37 

latent   38 

sensible   38 

specific    36 

transmission  of   260 

unit    36 

unit-value   of  indirect  radi- 
ation      90 

unit-value  per  sq.   ft 42 

Heat-loss — 

by  wind    24 

factors    15,  26 

from  floors    20 

from   fire-place    64 

from  partition-walls   51 

from   reception-hall 64 

from  rooms  in  buildings 14 

from   second-floor   room 72 

from  walls   21,  44 

from  warm  to  cold  room. . .  74 

from  windows   52 

table     ". 51 

Heating  measurements — 

rules    for    -. 97 

surface    165,235,257 

surface  and  fire-travel    245 

surface,    evaporative   power 
of   178 

High-pressure  data  174 

Hook-gage     5 

Horse-power    166 

radiation   of    177 

Hot-water  circulation — 

theory  of    286 

example  of    290 

Hot-water   heat,   first   instal- 
lation     274 

Hot-water  pressures,  table...   99 

Hot-water  system — 

essentials  in  selection 283 

overhead    31Z 

Hot-water  vs.  gravity  steam. 310 

House-wrecking   competition  327 

I 

Indirect-heating  rule   99 

Indirect-radiation—    

heat-unit  value  90 

sizing     85 

table    ...-. 88,  89 

Indirect   radiators    80 

Indirect-radiator   values... 86,  87 


H 


Head   of   water 277 

Head-pressure  307 

Heat- 
action   on   water 292 

emitted  from  cast-iron  radi- 
ators      34 


Latent  heat    38 

Low-pressure          steam-main, 
radiation  on   154 


M 


Main,    radiation   carried    by..  141 
Mains,  pipe  for  153 


XIV 


Manifold-coil  radiation   332 

Masonry — 

heat-loss    47 

increase    of    temperature...  22 

Measurement,   form   of    76 

Measurements  of  heat-loss...  14 

Miller  draft-gage    4 


Open-tank    system    299 

loss  in   323 

Overhead   steam-job    131 

Overhead-system,  hot- water.. 324 


Partition-walls,   heat  loss  in.   51 

Peclet   draft-gage    4 

Pipe-areas    158 

for  expansion-tank   321 

for   mains    153 

radiating  surface  of 188 

Pipe-coils,   first    1. 148 

Pipe  size 122,  151 

Pipe  sizes,   guide  to 128 

Pipe,  use  of  small 110 

water  contained  in   296,  297 

Pipes,     steam,     capacity     of, 

table  125 

Piping- 
length   equal    to    friction   of 

fittings   145 

plans    151 

steam 113 

systems     102 

Piping  and  water-line 104 

Piling    to    steam-radiators...  102 

Porch-ceiling  losses    72 

Power-boiler — 

capacity  of   171 

rating  of    166 

unit  of  .    .  .  170 

Power,    unit   of 169 

Pressure — 

and   radiation    40 

at  boiler   28 

atmospheric    4 

on  heating  system 294 

radiation-table    ~..   41 


Radiating  surface,  first  used. 331 

Radiation — 

and  pressure    40 

box-coil     332 

carried  by  main   141 

flat-coil    332 

how  to  figure 17 

manifold-coil    332 

measurement    for,    example 
of , .  75 


on       low-pressure       steam 

main     154 

per  horse-power   177 

per  square  foot 39 

pressure  table   41 

Radiators- 
altitude     55 

closed   system    149 

construction  of    329 

direct     80 

direct-indirect 80 

early  history    329 

estimation  of  heating  value. 337 

Gold  pin   140 

heating   value    334 

height  above  boile",  , 315 

indirect    80 

mattress    148 

Nason 149 

.    rating  of   330 

ratings,    gross    190 

sheet-iron     148 

size  of   335 

surface    333 

temperatures    33 

water-content  of    318 

Rate    of    radiation 39 

Rating — 

boiler    188 

catalog    179,    180 

gross   radiator    190 

of  boilers    250 

of  boilers  in  catalog 265 

of    power-boilers    166 

Reaming  pipe,   advantage  of.  158 
ends    140 

Reception-hall   heat-loss    ....   64 

Rules  for  figuring  radiation..   97 


Sealed  system,   piping  for.... 322 

Second-floor  room  losses 72 

Sensible  heat   38 

Single-pipe      steam      system, 

first    202 

Single-pipe  work    132 

Smoke-pipe    size    7 

Soot,  composition  of 229 

Specific  heat    36 

Specifications   by  architect. .  .249 

Stack-temperature    179,  187 

Steam — 

properties    of,    table 120 

radiators,    piping   to 102 

temperatures     at     different 

altitudes  29 

velocities    143 

Steam -heating — 

dimensions   of  pipe 157 

first    148 

first  installation  of 273 

Steam-main,  to  find  area  of.  128 


XV 


Steam-mains    for    single-pipe 

work    122,    123 

Steam-pipe,   dimension  of 157 

Steam-pipes,       capacity       of, 

table    125 

Steam-piping    113 

examples    116 

Steam-pressures — 

different,    figuring    with 98 

table     98 

Steaming    value    of    coal 183 

Steam-system,     essentials    in 

selection    of    283 

Systems   of   piping    102 


Temperature — 

difference     in     heating     cir- 
cuit    31,  32 

drop     31 

measurement 37 

water  in  boilers    260,   261 

Thermometer     37 

Trap,    first    steam 149 

Two-pipe  direct-heating  sys- 
tem      123 


U 

Unit    of    evaporation 169 

of  heat    36 

of  power 169 


Velocity    of    steam     109,143 


W 

Wall-exposure   47 

Wall -heat- 
loss  21,  44 

loss-table     51 

losses,   differences  in   49 

Water- 
acted   on  by   heat 292 

column    6 

expansion  of,  under  heat... 303 

head  of  277 

line  and  piping  104 

line    condensed   study  of... Ill 

quality  of,  in  pipe 296,  297 

specific  heat  of    36 

"  temperature  in  boilers. 260,  261 
varying  weight   in    circula- 
tion      301 

velocity  of,  in  pipes 304,  305 

weight    in    cu.    ft.    at    var- 
ious    temperatures .287 

Wind- 
affecting  wall  and  window- 
losses  54 

force    57 

influence    on    heat-loss 24 

pressure     57 

velocity  57 

velocity-table     59 

Window-loss-table  53 

Window-surface,  area  of.. 62,  63 

loss-table    60,  61 

Windows,  heat-loss  by 52 

Winds,  types  of   56 

Wooden    building,     heat-loss.  52 


XVI 


'Domestic  Engineering"  Cartoon  on  "False  Boiler 
Ratings"— The  Little  Girl  Who  Was  Lost 


Whose  Little  Girl  Are  You? 


A  Practical  Manual  of   Steam  and 
Hot- Water  Heating 


SECTION  1. 


It  is  believed  that  many  facts  connected  with  the  heat- 
ing of  dwelling-houses  by  steam  and  hot  water  are  not 
generally  available  to  the  greater  mass  of  steam-fitters, 
plumbers,  architects  and  owners.  This  is  largely  due  to 
this  information  being  locked  up  to  a  great  extent  in 
formulas,  which  many,  possibly  a  majority,  could  not 
understand. 

It  will  be  the  purpose  of  this  book  to  clearly  state 
the  more  important  facts  in  simple  form  and  entirely 
without  algebraic  designations,  or  formulas.  Those  who 
do  not  easily  comprehend  facts  when  expressed  in  the 
X.  Y.  Z.  forms  of  the  schools  will  have  at  their  command 
by  this  means,  not  only  the  results  of  all  the  formulas, 
but  the  reasons  for  each  step  in  the  construction  of  a 
house-heating  plant,  whether  steam  or  hot  water  be  used 
as  the  heating  medium. 

It  is  hoped  that  the  entire  process,  step  by  step,  can 
be  stated  so  simply  and  the  reason  for  each  step  so  clear- 
ly explained,  that  any  steam-fitter,  plumber,  or  mechanic, 
with  a  general  knowledge  of  the  use  of  the  materials 
and  tools  of  the  trade  can,  by  the  aid  of  this  series  of 
articles  proceed  to  measure  up  a  house  properly.  Such 
measurement  will  be  required  in  order  to  properly  de- 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

termine  the  loss  of  heat;  the  size  of  radiators  needed  to 
properly  replace  the  heat  lost ;  the  proper  sizes  of  piping 
to  convey  the  heating  medium  at  any  selected  gage-pres- 
sure in  steam  or  temperature  in  hot-water  heating;  and 
the  proper  size  and  type  of  boiler  to  use. 

It  is  a  matter  of  common  knowledge  that  there  are  a 
number  of  so-called  systems  or  methods  of  constructing 
house-heating  steam  and  hot-water  plants. 

But  it  is  not  generally  known,  apparently,  that  all 
these  various  systems  are  primarily  based  upon  the  ob- 
servance of  a  few  general  laws;  laws  as  certain  in  their 
action  as  the  laws  of  attraction  and  repulsion. 

There  have  been  many  books  written  and  many  rules 
given  for  students  of  heating  problems,  but  most  of 
these  have  been  prepared  to  exploit  some  individual 
idea,  or  some  one  particular  design,  or  type  of  construc- 
tion, with  the  result  that  persons  who  have  come  into 
the  possession  of  more  than  one  authority,  or  writer's 
rules,  usually  find  them  so  widely  at  variance  on  impor- 
tant points  as  to  be  bewildering. 

Because  of  these  well-known  variations,  thousands  of 
splendid  mechanics  in  the  plumbing  industry  have  been 
disinclined  to  take  up  the  most  desirable  portion  of  their 
business,  that  of  house-heating. 

We  believe  that  the  reader,  or  student,  who  will,  in 
these  pages,  carefully  follow  each  step  in  the  designing 
and  construction  of  house-heating  plants  for  steam  or 
hot  water,  will  have  no  difficulty  in  bringing  all  appar- 
ent differences  of  authorities  to  one  common  basis.  When 
this  is  done,  these  differences  will  be  reconciled,  except 
in  cases  where,  as  in  the  foreign  patented  systems,  an  ele- 
ment is  introduced  which  is  beyond  the  explanatory  scope 
of  this  present  book;  although  when  fully  studied  it 

2 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

will  be  found  these  systems  in  no  way  disagree  from 
the  fundamental  laws  explained  herein. 

With  these  few  words  of  introduction  we  will  start 
at  once  to  discuss  the  necessary  things  to  do  and  the 
reasons  for  doing  them,  preparatory  to  doing  a  steam 
or  hot-water  heating  job  in  an  ordinary  residence  build- 
ing. 

The  form  of  procedure  will  be  the  same,  whether  the 
building  be  one  that  has  been  occupied  for  years,  or  is 
being  prepared  for  first  occupancy,  and  whether  it  is  to 
be  heated  with  steam  or  hot  water. 

CHIMNEYS. 

The  first  thought  and  attention  should  be  given  to  the 
chimney-flue  construction  when  proposing  to  construct 
a  steam  or  hot-water  heating  plant.  Unless  this  is  prop- 
erly constructed,  6f  ample  size  and  height,  time,  money, 
patience  and  good  reputation  will  be  wasted  if  an  at- 
tempt is  made  to  connect  up  any  one  of  the  so-called 
systems  to  an  inadequate  chimney-flue. 

In  order  that  the  student,  or  general  reader,  may  un- 
derstand what  is  meant  by  an  inadequate  chimney-flue, 
it  will  be  necessary  at  this  point  to  explain  fully  certain 
facts  in  relation  to  chimneys  to  be  used  for  house-heat- 
ing boilers. 

The  chimney-flue  serves  a  double  purpose.  It  must 
not  only  maintain  a  relatively  steady  draft,  but  it  must 
also  lift  and  discharge  from  its  top  the  gases  and  smoke 
created  by  the  fuel-combustion  in  the  boiler. 

Among  heating  engineers  the  strength  of  draft  in 
a  chimney-flue  is  measured  by  the  number  of  inches  of 
water  required  to  equalize  it. 

For  the  benefit  of  those  of  our  readers  who  are  not 


A     Practical    Manual    of    Steam    and    Hot-Water    Heating 

familiar  with  the  measuring  devices  used  for  this  pur- 
pose, we  illustrate  and  describe  two  draft-gages  used 
extensively  throughout  the  country. 

The  Peclet  Draft-Gage. 

It  consists  of  a  bottle  A  with  a  mouth-piece  near  the 
bottom,  into  which  a  tube,  EB,  is  inserted  with  any 
convenient  inclination.  The  upper  end  of  the  tube  is 
bent  upward,  as  at  BK,  and  connected  with  a  rubber 
tube,  KC,  leading  to  the  chimney.  The  tube  is  fastened 
to  a  convenient  support,  and  a  level,  D,  is  attached. 

To  use  the  instrument,  first  level  it,  note  reading  of 


Fig.   1.     The  Peclet   Draft-Gage. 

scale,  then  attach  it  to  the  chimney,  and  take  the  reading, 
which  will  be,  if  the  inclination  is  one  to  five,  five  times 
the  difference  of  level  in  bottle  and  tube.  The  scale 
should  be  graduated  to  show  differences  of  level  in  the 
bottle,  and  thus  give  the  pressure  directly  in  inches  of 
water. 

The  Miller  Draft-Gage. 

This  consists  of  two  pieces  of  three-inch  brass  pipe 
connected  by  a  half-inch  pipe  at  bottom.  One  of  the 
pipes  is  closed  at  the  top  and  can  be  connected  to  the 
chimney  by  a  small  pipe  with  a  valve  as  shown.  The 
other  piece  of  brass  pipe  is  open  and  has  a  hook-gage 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

reading  to  1/1000  of  an  inch  suspended  in  it.  In  pre- 
paring for  a  reading,  the  closed  tube  or  leg  is  shut  off 
from  the  chimney  and  opened  to  the  atmosphere ;  the 
water  then  stands  at  the  same  height,  aa,  a1a1,  in  both 
legs.  The  closed  leg  is  now  shut  off  from  the  air  and 


Fig.   2.      The    Miller    Draft-Gage. 

connection  is  made  with  chimney,  whereupon  the  level 
falls  to  bb  in  the  open  leg  and  rises  to  b1!)1  in  the  closed 
leg.  As  the  two  legs  have  exactly  the  same  internal  di- 
ameter, the  fall  ab  is  half  the  draft,  measured  in  inches 
of  water.  The  hook-gage  is  set  to  the  level  aa  when  it  is 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

connected  to  the  chimney.  The  difference  of  the  read- 
ings multiplied  by  2  is  the  draft  in  in.  of  water.  The 
reading  by  the  hook-gage  can  readily  give  an  accuracy 
of  1/1000  of  an  inch,  which  is  sufficient  for  this  pur- 
pose. 

Hence  it  will  be  seen  that  a  column  of  water  27.77 
high  is  the  equivalent  of  one-pound  pressure  per  square 
inch  of  surface  upon  which  it  rests.  It  is  usual  to  say 
28  inches,  and  for  ordinary  computations  this  height  of 
water-column  is  used.  If  a  chimney-draft  was  balanced 
by  a  column  of  water  one  inch  high,  the  draft  strength 
would  be  1-28  of  a  pound  per  square  inch  of  area.  This 
is  not  considered  by  power-boiler  manufacturers  enough 
draft  for  their  product,  for  experience  and  experiment 
have  demonstrated  that  to  maintain  combustion  of  the 
various  coals  at  high-pressure  steam-producing  tempera- 
ture, a  minimum  draft  equivalent  to  a  column  of  water 
one  and  one-quarter  inches  high  is  needed  in  big  power 
plants  and  with  some  boiler  construction  even  as  high 
a  pressure,  or  draft,  as  will  balance  two  inches  of  water 
is  required.  Nearly  all  house-heating  boiler-manufac- 
turers of  present  time  require  that  a  chimney-draft  shall 
equal  the  pressure  of  one  fifteen-hundredths  of  an  inch 
of  water,  although  some  require  as  much  as  two-tenths 
of  an  inch.  But  the  chimney-flue  must  possess  some- 
thing more  than  draft. 

It  must  have  a  sufficient  area  in  square  inches  at  the 
specified  draft  to  permit  the  smoke  and  gases  produced 
from  a  given  quantity  of  fuel  at  varying  rates  of  com- 
bustion to  pass  through  the  flue  and  be  discharged  from 
the  top  without  excess  of  friction. 

The  varying  conditions  of  atmospheric  pressure,  at- 
mospheric temperature,  humidity  and  other  things  tend 

6 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

to  affect  the  specific  item  called  draft,  while  the  condi- 
tion of  the  fire,  the  quality  of  the  fuel,  as  well  as  the 
quantity  of  it,  are  constantly  affecting  the  work  the  chim- 
ney is  called  upon  to  do  in  delivering  freely  from  the 
chimney  top  the  smoke  and  gases  produced  by  the  fire 
in  the  boiler. 

Every  boiler-manufacturer  gives  in  his  catalog  the 
smoke-pipe  size  required  for  each  boiler  he  manufactures. 
This  smoke-pipe  area  represents  the  area  in  square  inches, 
of  free  or  frictionless  area,  which  a  chimney  with  not 
less  than  .15  in.  of  water-balancing  draft  must  have  to 
get  satisfactory  results  from  that  particular  boiler  when 
a  full  chaige  of  average  fuel  is  to  be  used.  Unless  a 
chimney  of  at  least  that  area  is  provided,  even  if  the  draft 
is  perfect  per  square  inch  of  sectional  area,  the  volume 
necessary  to  pass  through  the  flue  in  a  given  time  will  be 
restricted  and  the  boiler  will  either  fail  to  produce  steam 
at  all  or  it  will  do  so  in  fitful  spurts. 

If  a  manufacturer  furnishes  a  boiler  with  a  smoke- 
hood  eight  inches  in  diameter,  it  will  have  an  area  of 
50.265  sq.  in.,  or  practically  50,^4  sq.  in. 

To  attach  such  a  boiler  to  a  chimney  with  a  sectional 
area  of  less  than  50^4  sq.  in.  is  to  invite  probable  failure 
of  the  job,  even  if  every  other  portion  of  it  were  per- 
fect. 

The  height  of  a  chimney  adds  to  the  draft  as  measured 
by  the  water-gage  supposing  only  air,  and  lighter  than 
air,  gases  are  present.  But  the  matter  of  friction  must 
be  considered  when  the  whole  work  of  the  chimney  in 
draft  and  smoke-delivery  is  considered. 

Because  of  friction,  one  should  never,  under  any  con- 
ditions, accept  a  contract  and  garantee  results  where  the 
chimney-flue,  to  which  the  boiler  must  be  attached,  is 

7 


A     Practical    Manual    of     Steam    and    Hot-Water    Heatin^ 

only  four  inches  one  way.  Old  buildings  often  present 
flues  4x8  or  4x12  or  4x16  in.  If  the  owner  will  not  fur- 
nish a  round  or  square  chimney  of  required  area,  it  will 
be  the  part  of  wisdom  for  steam-heating  contractors 
to  decline  the  job. 


SECTION  II. 


Having  found  a  clear  flue  which  in  its  smallest  part  is 
equal  to,  or  exceeds  the  area  required  by  the  boiler  it  is 
intended  to  use  as  indicated  by  the  smoke-collar  on  the 
boiler,  the  next  thing  is  to  look  for  possible  objections 
to  the  proposed  flue,  either  at  the  top  or  the  bottom. 
Figs.  3  3  4  and  5. 

See  if  the  chimney-top  is  lower  than  any  projecting 
portion  of  the  building,  or  even  on  a  level  with  it ;  if  any 


nearby  building  towers  above  it ;  if  trees  grow  so  as  to 
obstruct  the  draft  when  the  wind  is  from  certain  direc- 
tions. If  everything  outside  is  unobjectionable,  look  at 
the  bottom  of  the  chimney-flue,  and  make  sure  provision 
is  made  so  that  the  bottom  of  the  flue  ends  not  more  than 
18  or  20  in.  below  the  point  where  you  intend  to  make 
the  smoke-pipe  connection.  A  good  practice  is  to  have 
a  close-fitting  slide-damper  placed  as  many  inches  below 

9 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 


the  bottom  of  the  smoke-pipe  as  the  pipe  is  inches  in 
diameter,  and  below  this  can  be  placed  a  clean-out  door 
if  the  owner  desires;  but  there  should  be  no  openings 
below  the  smoke-pipe  opening.  Next  look  for  fire- 
place or  stove-pipe  openings  into  the  chimney-flue  above 
the  smoke-pipe  to  the  boiler-opening.  If  any  are  found 
they  must  be  closed  and  sealed  tight  and  in  such  a  man- 
ner as  to  leave  the  chimney-flue  smooth  on  the  inside  if 
possible.  Lastly,  make  sure  that  the  capstone  of  the  chim- 
ney has  opening  sufficient  for  the  required  area. 


Fig.   4. 

Owners  often  put  on  capstones  with  two  or  more  open- 
ings, the  combined  area  of  which  may  be  from  25  to  40 
per  cent  only  of  the  area  of  the  chimney  proper. 

It  is  a  very  common  experience  to  find  an  8xl2-in. 
chimney  capped  with  a  stone  with  two  holes  in  it,  each 
5x6  in. ;  this  at  once  reduces  the  delivery-area  of  the 
chimney  from  96  sq.  in.  to  60  sq.  in.  Occasionally  an 
8xl2-in.  chimney  will  have  a  cap  with  two  4x6-in.  holes, 
thereby  cutting  the  delivery-area  of  the  chimney  down  to 
48  sq.  in.,  or,  of  no  more  value  than  a  6x8-in.  free  area. 

10 


A.    Practical    Manual    of    Steam    and    Hot-Water    Heating 


It  should  be  remembered  that  a  new  chimney  which 
has  a  large  amount  of  moisture  and  which  quickly  absorbs 
a  lot  of  heat  from  ascending  gases  will  not  have  as 
vigorous  a  draft  as  when  it  is  thoroughly  dried  out.  On 
the  other  hand,  do  not  assume  that  because  a  given  flue 
has  served  for  a  hot-air  furnace  that  it  will  answer  for 
a  steam  or  hot- water  job  to  heat  the  same  house.  The 
conditions  required  for  the  operation  of  a  steam-boiler 
or  a  hot-water  boiler  successfully  may  be  very  different 
from  that  required  by  the  hot-air  furnace. 

The  hot-air  furnace  may  not  have  [supplied  warmth  at 
one  time  to  more  than  half  the  number  of  cubic  feet  of 


Fig.   5. 

air  that  the  steam  or  hot-water  boiler  is  expected  to  heat 
all  the  time. 

Table  A  gives  the  areas  of  circles — From  this  table 
it  is  easy  to  determine  the  free  area  in  square  inches  a 
given  boiler  will  require.  For  instance,  a  boiler  which 
is  cataloged  to  require  a  10-in.  smoke-pipe  would  require 
a  chimney-area  of  not  less  than  78^  sq.  in.  and  it  is 
usual  to  use  with  such  a  boiler  an  8xl2-in.  chimney-pipe, 
or  a  10-in.  round  flue  if  the  chimney  is  45  ft.  to  60  ft. 
high  and  a  12-in.  round  .flue  if  the  chimney  is  20  or  30 
ft.  high.  Boiler-manufacturers  do  not  all  use  the  same 
size  smoke-flue  on  their  boilers  for  the  same  rated  capac- 

11 


TABLE  A. 
Areas  of  Circles. 


Size 

Area 

Size 

Area 

Size 

Area 

Size 

Area 

y* 

0.0123 

10 

78.54 

30 

706.86 

65 

3318.3 

% 

0.0491 

X 

86.59 

31 

754.76 

66 

3421.2 

3/8 

0.1104 

11 

95.03 

32 

804.24 

67 

3525.6 

X 

0.  1963 

X 

103.86 

33 

855.30 

68 

3631.6 

X 

0.3067 

12 

113.09 

34 

907.92 

69 

3739^2 

X 

0.4417 

X 

122.71 

35 

962  .  1  1 

70 

3848.4 

% 

0.6013 

13 

132..  73 

36 

1017-8 

71 

3959.2 

\ 

0.7854 

X 

143.13 

37 

1075.2 

72 

4071.5 

% 

0^9940 

14 

153  93 

38 

1134.1 

73 

4185.3 

X 

1.227 

'X 

165.13 

39 

1194.5 

74 

4300.8 

y* 

1.484 

15 

176.71 

40 

1256.6 

75 

4417.8 

x 

1  :  767 

X 

188.69 

41 

1320.2 

76 

4536.4 

X 

2.073 

16 

201.06 

42 

1385.4 

77 

4656.0 

% 

2  405 

l/2 

213.82 

43 

1452  2 

78 

4778.3 

y* 

2.761 

17 

226.98 

44 

1520.5 

79 

4901.6 

2 

3  141 

X 

240.52 

45 

1590.4 

80 

5026.5 

X 

3.976 

18 

254.46 

46 

1661.9 

81 

5153.0 

% 

4.908 

X 

268.80 

47 

1734.9 

82 

5281.0 

X 

5.939 

19 

283  52 

48 

1809,5 

83 

5410.6 

3 

7.068 

X 

298.64 

49 

1885.7 

84 

5541.7 

X 

8.295 

20<M> 

314.16 

50 

1963  5 

85 

5674.5 

l/2 

9.621 

X 

330.06 

51 

2042.8 

86 

5808.8 

y* 

11.044 

21 

346.36 

52 

.2123.7 

87 

5944.6 

4 

J2.566 

K 

363  05 

53 

2206  1 

88 

6082  1 

X 

*15.904 

22 

380.13 

54 

2290.2 

89 

6221  .  1 

5 

19.635 

X 

397.60 

55 

2375.8 

90 

6361.7 

X 

23.758 

23 

415.47 

56 

2463.0 

VI 

6503.8 

6 

28.274 

K 

433.73 

57 

2551.7 

92 

6647.6 

X 

33.183 

24 

452.39 

58 

2642.0 

93 

6792.9 

7. 

38.484 

X 

471.43 

59 

2733.9 

94 

6939.7 

X 

44,178 

25 

490.87 

60 

2827.4 

95 

7088  2 

8 

56.265 

26 

530.93 

61 

2922.4 

96 

7238.2 

X 

56.745 

27 

572  55 

62 

3019.0 

97 

7389.8 

9 

63.617 

28 

615.75 

63 

3117.2 

98 

7542.9 

X 

70.882 

29 

660.52 

64 

3216.9 

99 

7697.7 

To  find  the  circumference  of  a  circle  when  diameter  is  given,  multiply 
the  given  diameter  by  3.1416. 

To  find  the  diameter  of  a  circle  when  circumference  is  given,  multiply 
the  given  circumference  by  .31831. 


12 


A    Practical    Manual    of    Steam    and    Hot- Water    Heating 


ity  in  square  feet  of  radiation;  therefore,  no  exact  rule 
for  chimney-size  per  hundred  feet  of  radiation  can  be 
given,  but  in  a  general  way  Table  B  will  be  found  suffi- 
ciently accurate. 

When  using  Table  A  for  ascertaining  the  chimney- 
area  required,  always  select  the  area  next  larger  in 
square-edged  flues,  unless  the  exact  size  is  found.  For 
example,  if  a  boiler  has  a  9-in.  smoke-pipe,  Table  A 
shows  a  9-in.  circle  has  an  area  of  63.6  sq.  in.,  and  you 
note  an  8x8-in.  chimney-flue  has  64  sq.  in.  It  would 
evidently  not  do  to  use  an  8x8-in.  flue,  because  in  order 

TABLE  B. 

Approximate  sizes-  of  Chimney-Flues  for  Steam  and 
Hot- Water  Heating  in  Residences  and  other  Buildings. 


DlKK.CT   RADIATION* 

SIZE  OF  FLUE 

Steam  in 
Square  Feet 

Water  in 
Square  Feet 

Round 

Square 

250 

400 

8 

8x8 

300 

500 

8 

8x8 

400 

700 

8 

8  x  8 

500 

850 

10 

8x  12 

600 

1000 

10 

8x12 

700 

1200 

10 

8x  12 

800 

1350 

12 

12x  12 

900 

1500 

12 

12x  12 

1000 

1700 

12 

12x  12 

1200 

2100 

12 

12  x  12 

1400 

2400 

14 

12  x  16 

1600 

2700 

14 

12  x  16 

1800 

3000 

14 

12  x  16 

2000 

3400 

14 

12  x  16 

2200 

3700 

16 

1  6  x  16 

3000 

5100 

16 

16x16 

3500 

5900 

18 

1  6  x  20 

5000 

8500 

18 

16  x  20 

increased  Boiler  Capacity  is  necessary  and   in   many   cases  such,  demands  require  a 
larger  chimney  flue  for  same  number  of  square  feet  of  radiation  used. 

to  do  it,  you  must  reduce  the  manufacturer's  required 
area  for  the  proper  working  of  his  boiler  from  9  to  8  in., 
or  from  63.6  sq.  in.  to  50*4  sq.  in.  This  means  that  the 


13 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

boiler  as  designed,  has  at  this  vital  point  been  choked  over 
20  per  cent — and  it  is  certain  that  no  machine,  rated  to  do 
certain  work  when  all  its  component  parts  are  perfect, 
can  reasonably  be  expected  to  do  the  same  work,  and 
equally  well,  when  over  20  per  cent  of  any  one  of  its 
vital  points  of  construction  is  taken  away. 

To  Determine  Amount  of  Heat-Loss  From  Rooms  in 
Buildings — Measurements. 

This  question  of  the  proper  "figuring  for  radiation" 
is  not  an  easy  one  to  solve  and  the  task  is  not  made  easier 
when  the  solution  is  to  be  attempted  without  resorting 
to  algebra. 

As  a  matter  of  fact  there  is  no  "hard  and  fast  rule" 
applicable  without  change  or  modification  to  each  and 
every  condition. 

The  mere  fact  that  two  rooms  are  15  ft.  square  and 
10  ft.  high,  with  a  cubic  content  of  2,250  cu.  ft.  each, 
does  not  determine  that  there  will  be  the  same  amount 
of  heat  required  in  each  to  maintain  70  deg.  in  each  room 
when  it  is  zero  outside.  If  it  did,  the  task  of  estimating 
the  required  amount  of  radiator-surface  would  be  simple. 

It  requires  no  argument,  or  illustration,  to  demonstrate 
that  if  a  given  room  shows  a  temperature  of  70  deg.  at 
one  time  of  the  day,  and  zero  at  another  hour,  that  there 
has  been  a  loss  of  70  deg.  of  heat.  It  is  also  evident 
that  if  the  doors,  windows,  or  other  openings  have  been 
tightly  closed  between  the  period  when  the  room  was  at 
70  deg.  until  it  reached  zero,  that  the  heat  must  have 
in  some  way,  passed  through  either  walls,  floors,  ceiling 
or  doors  and  windows,  or,  that  each  of  them  had  con- 
tributed its  proportion  of  the  loss. 

This  much  granted,  the  next  step  is  to  determine  how 

14 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

much  of  the  total  loss  each  factor  has  contributed.  Un- 
less this  can  be  determined  with  considerable  exactness  it 
would  be  the  rankest  sort  of  guesswork  to  attempt  to 
"figure"  for  radiator-surface. 

Fortunately,  science  and  experiment  have  determined 
with  considerable  exactness  the  number  of  units  of  heat 
which  a  square  foot  of  window-glass  will  permit  to  pass 
through  it  in  a  given  length  of  time  if  one  side  of  it  is 
at  70  deg.  F.,  and  the  other  side  has  a  temperature  of 
zero.  All  the  other  factors,  walls,  doors,  floors,  ceilings 
— are  found  to  be  contributors  to  the  total  loss,  each  in 
its  own  proportion.  As  heat  never  passes  from  a  cooler 
body  to  a  warmer  one,  it  follows  that  the  colder  the 
surrounding  or  connecting  body  the  greater  will  be  the 
loss  in  a  given  time  from  the  warmer.  Therefore  not  a 
single  factor  which  goes  to  create  the  room  will  lose 
the  same  amount  of  heat  under  all  conditions.  Again  it 
is  not  necessary  to  illustrate  by  argument  that  a  brick  wall 
9  or  10  in.  thick  will  not  lose  as  much  heat  through  a 
square  foot  of  its  surface  under  varying  temperatures  as 
would  be  lost  through  a  square  foot  of  window-glass. 

The  point  to  find  out  is  how  much  of  the  total  loss, 
each  hour,  does  each  factor  furnish,  and,  having  found 
this,  the  next  step  will  be,  how  to  so  arrange  the  heating 
surface  that  it  shall  balance  the  hourly  loss  from  all 
sources  and  thereby  maintain  the  room  at  a  steady  tem- 
perature. 

It  would  not  seem  necessary  to  advance  an  argument 
to  demonstrate  that  a  rule,  for  the  proper  proportioning 
of  heating  surface  in  a  room,  whose  total  loss  of  heat 
was  created  by  losses  through  various  factors,  could 
only  be  made  by  carefully  ascertaining  the  amount  lost 

15 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

by  each  factor,  and  when  this  had  been  found  that  the 
proper  rule  for  supplying  this  loss  from  a  heated  body 
would  depend  entirely  upon  the  temperature  of  the  heated 
body. 


16 


SECTION  III. 


.Yet,  simple  as  this  proposition  seems,  the  great  mass 
of  the  steam-fitting  trade  of  this  country  is  trying  to  make 
a  radiator  at  a  temperature  of  a  trifle  over  200  deg.  at 
its  surface  work  satisfactorily,  when  the  figures,  upon 
which  they  base  the  surface,  require  a  temperature  40 
to  50  deg.  higher  by  many  of  the  rules. 

Under  present  commercial  ratings  of  boilers  for  both 
steam  and  water,  the  majority  of  rules  in  use,  even  those 
based  upon  correct  measurements  of  wall  and  window 
surface,  are  but  little  better  than  the  old  "rule  of  thumb" 
guess-work  ratio  rules.  . 

It  is  time  that  some  of  the  simple  facts  be  plainly  set 
forth  and  the  trade  be  shown  how  to  figure  radiation 
:orrectly  at  any  required  temperature  of  steam  or  water. 

I  realize  that  in  attempting  this  it  will  be  necessary 
to  go  over  some  ground  that  will  seem  almost  trivial  to 
many.  The  heating  engineer,  however,  who  gets  out  into 
the  highways  and  by-ways,  will  appreciate  how  often 
and  in  what  unexpected  quarters  he  is  asked  to  show  cus- 
tomers how  to  measure  a  room.  It  is  the  purpose  here 
to  go  into  sufficient  detail  in  all  essential  points  to  cover 
the  questions  that  have  been  constantly  presented  to  me 
by  customers  through  the  many  years  that  have  elapsed 
since  I  first  began  answering  such  questions.  It  is,  first 
of  all,  necessary  to  measure  the  length,  width,  and  height 
of  each  room,  and  multiply  the  length  by  the  width  and 
that  sum  by  the  height  to  secure  the  cubic  contents  of  the 
room.  Suppose  we  have  a  room  16  ft.  long,  15  ft.  wide 

17 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 


and  11  ft.  high.     The  length  and  width  multiplied,  16  X 
15  =  240;  this  multiplied  by  11  =  2,640  cu.  ft. 

We  have  agreed  that  the  heat  is  lost  through  all  fac- 
tors composing  the  room.    We  have  found  the  cubic  con- 

FORM 


Measurements  and  figuring  data  from 

House   of    

Street  No 

Telephone  No 

R.   F.   D.   No.. 


Rough  Sketch  of  Rooms 


Name  of  Room  and 

Temperature  Required 

§ 

* 

Compass  location. 
Feet  exposed  wall. 
Prevailing  wind. 
Elevation  above  sea. 

Kind  of  wall 
and  condition. 

Size  of  room  in 
Feet  and  inches. 

Number,  size  and 
kind  of  windows. 

Number,  size  and 
kind  of  Doors  to  out- 
side air  or  Colder 
Rooms. 

A  Useful  Form  of  Measuring  Up  and 
18 


A     Practical    Manual    of     Steam    and    Hot- Water    Heating 

tents,  but  unless  we  find  how  many  heat  units  are  lost 
each  hour  through  walls,  windows,  floors,  ceilings  and 
probable  leakage,  what  good  will  the  knowledge  of  cubic 
contents  do  ?  We  must  now  look  for  exposed  walls.  By 


AB. 


t Architect 

Street    

Town    

County    « 

State    . 


or  Floor  in  this  Space. 


Temperature 
Cold  air. 


Square  feet 
Exposed   floor. 

Temperature  of 
Cold  side  of  floor. 


Square  feet 
Exposed  ceiling 
Roof  or  side 
of  Bay  window. 

Temperature  of 
Cold  side. 


General  Remarks. 


Calculating  on  a  Proposed  Installation. 


19 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

this  is  meant,  walls  exposed  to  the  outside  air,  and  also 
walls  exposed  to  cold  inside  rooms.  The  fitter  must 
never,  for  a  moment,  forget  while  measuring  a  room 
for  heat-loss,  that  heat  will  always  pass  to  a  colder  body 
with  which  it  is  in  contact,  and  if  one  side  of  a  room  is 
to  have  on  its  outer  side  a  cold  room,  note  must  be  taken 
of  it,  just  as  surely  as  though  the  other  side  of  the  wall 
was  surrounded  by  out-door  air. 

"The  fitter  who  is  preparing  to  "measure  up  a  house  for 
heating,"  should  first  prepare  a  form  upon  which  he  can 
quickly  and  accurately  place  the  data  he  requires,  and 
without  which  he  can  only  do  a  guesswork  job. 

A  form,  something  like  Form  AB,  answers  very  well, 
although  some  find  more  elaborate  ones  desirable,  but  for 
ordinary  residence-work  the  dhe  here  given  serves  very 
well. 

Care  must  be  exercised  with  regard  to  floors.  Many 
houses  have  cellars  under  a  few  rooms.  Some,  in  the 
South  and  Middle  West,  have  no  cellars  at  all,  the  houses 
being  built  on  piers.  In  all  sections,  rooms  on  the  second 
floor  will  be  found  with  the  whole,  or  a  portion,  of  a  floor 
space  over  an  open  porch,  and  often  with  unusual  wind- 
exposure.  All  such  conditions  must  be  met  by  extra 
radiation  to  supply  the  loss.  Another  very  common  con- 
dition, and  one  often  overlooked,  is  the  thin  flat  roof 
over  a  room  which  may  have  been  added  to  an  old  house. 
Such  a  roof  dissipates  heat  wonderfully  as  we  shall  dis- 
cover later,  when  the  measurements  have  been  made  and 
we  begin  to  count  up  the  heat-loss  through  each  factor. 

We  now  find  the  square  feet  of  wall  surface  exposed 
to  colder  air  than  the  room  we  are  preparing  to  heat. 

Suppose  the  room  we  used  to  illustrate  the  cubic-con- 
tents rule  has  one  side  16x11  ft.,  and  one  end  15x11 

20 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

ft.  exposed  to  the  out-door  air.  In  addition,  there  are 
also  four  windows,  each  of  which  are  6  ft.  10  in.  x  3  ft. 
8  in,  the  first  thing  usually  done  is  to  get  the  gross  square 
feet  of  exposed  wall  surface  and  from  this  deduct  the 
window-opening.  The  end  and  side-wall  lengths  equal 
16  +  15  =  31  ft. ;  the  height  is  11  ft. ;  then  the  total 
length,  31  ft.  multiplied  by  the  height,  11  ft.  =  341  gross 
sq.  ft.  There  are  four  windows,  each  6  ft.  10  in.  x  3  ft.  8 
in.,  or  25  sq.  ft. ;  then  25  X  4  =  100  sq.  ft.  of  window. 
Deducting  this  from  the  gross  wall  surface  and  the  real 
exposed  wall  is  341  —  100  =  241  sq.  ft.  real  wall.  The 
material  of  which  the  wall  is  constructed,  and  its  con- 
dition is  now  to  be  noted. 

There  is  not  much  difference  in  the  loss  of  heat  per 
square  foot,  between  a'  well-built  wooden  wall,  cross- 
boarded,  well-papered  and  clapboarded,  and  a  well-built 
hard  brick  house  wall.  Not  nearly  so  much  difference 
as  often  exists  between  two  brick  walls. 

While  we  shall  have  to 'refer  to  this  part  of  the  subject 
again,  it  seems  important  to  take  up  this  matter  of  walls 
at  some  length  right  now,  in  order  to  explain  the  abso- 
lute necessity  of  securing  data  regarding  them  for  future 
use. 

It  has  not  been  called  to  the  attention  of  the  trade 
generally,  I  think,  that  a  vast  difference  in  loss  of  heat-, 
averages,  occurs  in  brick  buildings  of  identical  areas. 
I  do  not  think  it  had  occurred  to  anyone  to  investigate 
it  until  concrete-block  houses  began  to  be  quite  generally 
used.  Occasionally  some  fitter  would  find  himself  in 
trouble  with  a  brick-house-heating  plant  in  wet,  windy 
weather,  and  usually  blamed  the  chimney  or  the  fireman, 
or  most  anything  except  the  real  cause. 

Recent  investigations  have  shown  that  fine  hard  brick 

21 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

will  rarely  absorb  over  5  per  cent  of  their  weight  of 
water ;  good  brick,  not  over  10  per  cent ;  while  many  soft 
brick  take  up  from  25  to  40  per  cent  of  their  weight  of 
water.  Improved  methods  of  producing  cheap  brick  have 
enabled  contractors  to  secure  good-appearing  brick,  with 
a  ringing  sound  when  struck,  that  will,  notwithstanding 
their  good  appearance,  absorb  water  like  concrete. 

When  it  is  remembered  that  one  heat-unit  is  the 
amount  of  heat  required  to  raise  one  pound  of  water 
one  degree  of  temperature  and  that  that  same  amount 
of  heat  will  raise  five  pounds  of  dry  masonry  one  de- 
gree, the  necessity  of  noting  the  quality  of  brick  in 
walls  becomes  very  evident  to  one  who  is  to  come 
under  contract  to  furnish  heat  in  all  weathers.  In 
some  sections  of  the  country,  it  is  the  habit  to  use 
fine  hard  brick  of  the  best  grade,  for  the  front  portion 
of  buildings  and  cheap  brick  for  the  rear  sides  and 
end.  It  is  usually  this  portion  of  the  building  where 
heating  complaints  originate  in  wet  weather. 

It  is  not  unusual  to  find  rooms  finished  close  under 
the  roof.  These  rooms  should  be  measured  with 
great  care,  especially  the  ceiling,  when  lathed  and 
plastered  close  to  the  roof.  Surface  of  this  kind  is 
especially  affected  by  both  wind  and  moisture. 

If  the  building  is  of  concrete,  either  block  or  poured, 
special  attention  should  be  then  given  to  finding  out  if 
it  has  been  water-proofed,  and  to  what  extent;  also 
if  plastered  directly  on  the  concrete,  or  if  studded  and 
lathed  inside  the  concrete  wall. 

If  studded,  lathed  and  plastered,  an  increase  of  15 
per  cent  when  the  outside  wall  of  concrete  has  not 
been  water-proofed  will  usually  be  sufficient.  If  plas- 
tered directly  on  to  the  concrete,  it  will  be  found  very 

22 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

difficult  to  provide  sufficient  radiation  to  keep  the 
rooms  both  warm  and  dry  in  wet  weather.  An  excess 
of  about  60  per  cent  with  some  grades  of  concrete  will 
not  be  too  much  allowance  for  wet  weather,  accom- 
panied by  high  winds,  while  in  dry  weather,  the  same 
amount  of  radiation  required  for  first-class  brick  walls 
is  ample.  Concrete  which  has  been  thoroughly  water- 
proofed throughout  its  entire  structure,  or  which  has 
been  water-proofed  on  all  its  surface  inside  and  out  in 
block  construction,  makes  an  ideal  wall  from  a  heating 
point  of  view.  Just  in  proportion,  however,  that  con- 
crete absorbs  water  does  it  depart  from  the  ideal. 

The  steam-fitter  and  owner  should  constantly  bear 
in  mind  the  fact  that  water  is  the  greatest  absorber  of 
heat  known.  If  a  building  is  constructed  of  material 
that  absorbs  and  holds  large  quantities  of  moisture,  a 
corresponding  excess  of  heat  must  be  furnished  during 
any  period  of  excessive  moisture. 


23 


SECTION  IV. 


Another  important  reason  for  noting  down  at  time 
of  measurement  the  kind  and  condition  of  outside  wall 
of  each  room  measured  is  that,  very  often  the  rooms, 
having  porous  walls,  are  on  the  side  of  the  building 
most  exposed  to  the  winter  winds,  and  moisture  with 
wind  in  addition,  unless  especially  provided  against, 
will  cause  trouble  for  the  steam-fitter. 

The  prevailing  winter  wind  in  a  town  may  not  be 
the  prevailing  wind  direction  at  a  given  point  in  that 
town ;  thus,  while  the  prevailing  wind  in  the  town 
might  be  Northwest ;  at  a  given  point,  because  of  con- 
ditions created  by  eddies,  a  room  or  a  house  may 
receive  its  winter  wind  from  a  point  of  compass  some- 
what different.  The  points  of  compass  should  always 
be  included  with  the  pencil  sketch  of  floor  plans  of 
house,  and  they  should  always  head  the  lists  of  meas- 
urements. 

This  sketch  need  not  be  finely  drawn  or  in  great 
detail,  but  should  always  be  given.  The  contract  may 
not  be  awarded  at  once;  conditions  of  structure  may 
be  changed  after  your  measurements ;  memory  regard- 
ing the  relative  position  of  some  room  may  fail ;  many 
things  may  arise  that  would  make  the  rough  sketch  of 
great  value.  It  takes  but  a  moment  to  make  it,  and 
later,  may  save  a  long  trip  and  hours  of  time.  Never 
neglect  the  rough  sketch  even  on  the  simplest  jobs. 

When  measuring  for  square  feet  of  window-opening 
or  frame,  special  attention  should  be  given  to  the  man- 

24 


A    Practical    Manual    of    Steam    and    Hot-Water    rfeating 

ner  in  which  the  work  of  setting  window-frame  has 
been  performed.  A  great  many  instances  will  be 
found  where,  if  the  finish  boards  were  removed,  an 
area  equal  to  anywhere  from  one  to  three  square  feet 
of  surface  would  exist  where  the  only  protection  is 
the  finish.  Around  these  finish-boards,  there  will  be 
a  leakage  of  heat  requiring  careful  attention.  The 
leakage  in  a  well-built  house  will  usually  equal  twice 
its  cubic  contents  per  hour  from  the  first-floor  rooms, 
where  the  doors  opening  to  outside  usually  are  in 
excess  of  similar  doors  on  second  floor.  Second-floor 
leakage  is  rarely  less  than  the  equal  of  the  cubic  con- 
tents once  an  hour.  If,  however,  careless  construc- 
tion around  doors  and  windows  permits  a  still  greater 
loss,  some  provision  for  radiator  surface  to  offset  the 
excess  loss  must  be  made. 

From  the  foregoing,  the  absolute  necessity  of  com- 
plete data  as  indicated  will  be  readily  understood, 
even  at  this  very  early  stage  of  the  proceedings.  Later, 
when  we  come  to  figuring  heat-losses,  and  selecting 
radiator  surface,  piping,  and  a  suitable  boiler,  the  value 
of  this  preliminary  accuracy  becomes  startlingly  ap- 
parent. 

It  should  be  distinctly  understood  that  there  is  no 
"short-cut  road"  to  successful  steam-heating,  and  it  is 
equally  true  that  there  is  no  mystic  knowledge  re- 
quired. The  whole  proposition  of  house-heating  is 
founded  on  a  common-sense  understanding  of  a  very 
few  natural  laws.  The  very  first  of  these  is  that,  if 
two  units  of  heat  are  taken  from  any  larger  number 
of  units,  two  units  added  will  make  up  for  the  original 
loss.  "The  profession  of  steam  and  hot-water  heating 
is  not  as  yet  an  absolutely  exact  scientific  profession 

25 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

in  its  application  because  of  the  varying  conditions 
imposed.  But  it  is  scientific  and  exact  when  applied  to 
an  unvarying  condition.  The  action  of  heat  upon  air, 
water  and  various  substances  has  been  ascertained 
from  scientific  theory  and  experiment,  to  be  always 
the  same  under  the  same  conditions.  The  more  com- 
pletely the  conditions  are  ascertained  under  which 
heat  may  pass  from  a  warmer  to  a  colder  condition, 
the  more  accurate  can  the  provision  for  exactly  sup- 
plying the  needed  heat  to  maintain  the  warmer  body 
at  a  uniform  temperature  be  made. 

From  the  measurements  of  all  the  rooms  to  be 
heated  we  must  be  able  to  secure  the  following  details 
as  a  base  of  further  and  final  figuring. 

The  cubic  contents  of  each  room. 

The  square  feet  of  real  exposed  wall. 

The  square  feet  of  wall  exposed  to  colder  rooms. 

The  temperature  of  colder  adjoining  rooms  (usually 
32  degrees). 

The  square  feet  of  window-openings. 

The  square  feet  of  outside   door-openings. 

The  square  feet  of  floor  exposed  to  outside  air. 

The  square  feet  of  floor  exposed  to  cold  cellar  (usu- 
ally 32  degrees). 

The  square  feet  of  floor  exposed  to  colder  room 
(usually  32  degrees). 

The  square  feet  of  ceiling  exposed  to  colder  room. 

The  square  feet  of  ceiling  exposed  to  outer  air. 

The  kind  and  condition  of  walls. 

The  direction  of  prevailing  winter  wind. 

The  relation  of  each  room  to  point  of  compass. 

The  data  of  any  other  fact  bearing  upon  probable 

26 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

loss  of  heat  from  any  room  which  it  is  proposed  to 
maintain  at  a  steady  temperature. 

We  are  then  ready  to  consider  the  probable  loss  of 
heat  through  each  factor  mentioned. 

To  Determine  Amount  of  Heat-Loss  From  Rooms  in 
Buildings — Effect  of  Altitude. 

The  cubic  content  of  a  room  has  long  been  the 
factor  upon  which  guesswork  rules  have  been  hung. 
One  man  requires  the  use  of  one  square  foot  of  radia- 
tion for  every  30  cu.  ft.  of  air ;  another  says  you  must 
use  one  square  foot  for  50  cu.  ft.  out  of  the  total  cubic 
content.  A  third  man  says  you  must  use  judgment 
(which  is  certainly  sane  and  sagacious  advice)  and  use 
one  square  foot  to  from  35  to  60  cu.,  ft.  All  sorts 
of  rules  have  been  advanced  from  time  to  time  which, 
without  question,  were  practical  rules  for  a  certain 
locality  and  a  certain  type  of  building,  but  which, 
under  other  conditions,  would  be  without  value.  One 
noticeable  omission  in  all  "Rules  of  Thumb,"  as  Pro- 
fessor Carpenter,  of  Cornell  University,  designates 
them,  is  that  none  of  them  state  what  pressure  of 
steam  is  to  be  carried  or  what  temperature  the  water  in 
a  hot-water  job  is  supposed  to  attain. 

If  a  room  with  2,600  cu.  ft.  of  contents  is  to  be  heated 
from  a  radiator  based  upon  the  ratio  of  1  to  30,  or,  say, 
87  sq.  ft.  by  one  man ;  and  the  same  room  is  to  be 
heated  by  another  with  a  radiator  based  upon  a  ratio 
of  1  to  60,  or,  say,  44  sq.  ft.;  it  is  evident  that  the 
temperature  of  the  steam  in  one  radiator  must  be  much 
lower  than  in  the  other. 

Yet,  each  man  might  secure  the  same  results  in  room 
temperature,  the  reason  being  that  the  first  man  might 

27 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

require  a  pressure  at  his  boiler  of  5  Ib.  per  sq.  in., 
and  the  second  man  would  need  approximately  a  30-lb. 
pressure  per  sq.  in.  at  his  boiler.  This  one  illustration 
is  sufficient  to  show  the  absurdity  of  competing  for 
steam-heating  work  when  only  70  deg.  in  the  room  is 
required  and  the  job  is  to  go  to  lowest  bidder,  nothing 
whatever  being  said  by  owner  or  architect  in  regard  to 
pressure  to  be  carried. 

But  supposing  it  is  stipulated  that  only  2-lb.  pressure 
is  to  be  carried  at  the  boiler,  which  ratio  rule  would 
you  select? 

Again,  suppose  one  has  graduated  from  the  ratio- 
rule  class,  and  is  using  some  rule  based  upon  exposed 
wall  and  window  surface — 

Does  he  know  what  pressure  he  must  carry  to  make 
the  rule  universal?  Will  the  same  rule  that  works 
perfectly  in  results  when  applied  to  a  house  in  New 
York  City,  or  Boston,  give  the  same  results  when 
applied  to  a  house  built  from  the  same  plans,  by  the 
same  builder,  using  throughout  the  same  quality  of 
material  at  Denver?  A  trial  convinces  that  at  zero 
outside,  the  rule  that  gives  sufficient  radiation  to  se- 
cure 70  deg.  in  a  house  in  New  York  or  Boston  will 
not  heat  to  70  deg.  a  similar  house  in  Denver,  with  the 
same  gage-pressure. 

There  can  never  be  a  result  without  a  cause.  It  is 
also  evident  that  a  rule  that  does  not  meet  all  condi- 
tions is  incomplete.  In  order  to  clearly  explain  the 
cause  of  such  varying  results,  we  must  investigate 
more  fully.  If  we  find  that  a  ratio-rule  that  works 
out  well  in  Boston  fails  utterly  in  Denver  or  Lead- 
ville,  Colo.,  or  in  the  "Land  of  the  Sky,"  North  Caro- 

28 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

lina,  reasons  for  the  discrepancy  must  be  sought  and 
found. 

Those  rules  are  worthless,  not  only  because  of  differ- 
ence of  temperature  in  places  named,  but  they  do  not 
zvork  out  in  practice  at  the  same  outside  and  inside  tem- 
peratures because  of  difference  in  altitude. 

The  steam  that  is  produced  at  approximately  212 
deg.  F.  temperature,  is  produced  near  sea-level  under 
a  barometric  pressure  equal  to  29.905  in.  of  mercury, 
or  as  usually  stated  at  30  in.  mercury-pressure.  This 
just  balances  the  weight  or  pressure  of  the  atmosphere 
at  sea-level. 

As  one  ascends  above  the  sea-level,  this  pressure  or 
weight  grows  less  and  less  and  consequently  steam  is 
produced  from  water  at  a  correspondingly  lower  tem- 
perature; in  other  words,  it  is  not  as  hot. 

The  decrease  in  atmospheric  pressure,  as  one  rises 
above  sea-level,  is  not  exactly  constant,  as  shown  by 
the  sinking  mercury  in  the  barometer,  but  approxi- 
mately, the  barometer-mercury  sinks  one  inch  for  each 
1,000  ft.  above  the  sea-level. 

The  Encyclopedia  Britannica,  Vol.  Ill,  Page  387, 
gives  the  following  table  of  the  boiling  temperature  of 
pure  water  at  different  pressures  of  mercury: 

TABLE  C. 

Temperature  Fahr.  Barometer 

at  which  Water  Boils  Inches 

under  varying  of 

Barometer  Pressures.  Mercury 

212  29.905 

211  29.331 

210  28.751 

209  28.180 

208  27.618 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

Temperature  Fahr.  Barometer 

at   which    Water    Boils  Inches 

under  varying  of 

Barometer  Pressures.  Mercury 

207  27.066 

206  26.523 

205  25.990 

204  25.465 

203  24.949 

202  24.442 

201  23.943 

200  23.453 

For  practical  purposes,  in  determining  the  amount 
of  heat  a  square  foot  of  radiator  surface  will  emit  at 
different  altitudes  with  steam  or  hot  water  as  the  heat- 
ing medium,  it  will  do  to  assume  that  a  decrease  in  the 
atmospheric  pressure  due  to  altitude  equivalent  to  one- 
half  inch  of  mercury  occurs  for  every  500  ft.  above 
sea-level,  and  a  corresponding  drop  of  one  degree  F. 
in  the  temperature  of  steam,  or  if  you  prefer,  in  the 
boiling  point  of  water,  or  of  the  point  of  evaporation. 

In  other  words,  steam  without  pressure  other  than 
that  of  atmosphere  is  one  degree  F.  hotter  at  sea-level 
than  it  is  500  ft.  higher  up.  and  at  1,000  ft.  above  sea- 
level,  steam  creates  at  210  deg.  F.  This  is,  as  will  be 
seen  by  table  C,  within  154  thousandths  of  an  inch  of 
corrected  mercury-height  of  barometer-pressure  for 
1,000  ft. 

On  this  basis  the  boiling  point  of  water,  or  the  tem- 
perature of  steam  at  various  altitudes  can  be  figured 
with  sufficient  accuracy  for  house-heating  purposes 
as  per  table  D. 

30 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

TABLE  D. 

Boiling  Point  of  Water 

or 

Point  of  Evaporation 
Feet  above  sea-level.  into  Steam.  Degree  Fahr. 

0  212 

500  211 

1,000  210 

1,500  209 

2,000  208 

2,500  207 

3,000  206 

3,500  205 

4,000  204 

4,500  203 

5,000  202 

5,500  201 

6,000  200 

6,500  199 

7,000  198 

7,500  197 

8,000  196 

8,500  195 

9,000  194 

9,500  193 

10,000  192 

As  the  number  of  heat  units  given  off  or  emitted 
per  square  foot  per  hour  from  effective  radiator  sur- 
face is  determined  by  the  difference  of  temperature 
between  the  surface  of  the  radiator  and  the  mean  tem- 
perature of  the  surrounding-  air,  it  is  very  evident  that 
the  temperature  of  the  heating  medium  at  its  point 
of  evaporation  becomes  a  most  important  factor  in 
applying  a  ratio-rule  or  a  rule  with  an  unknown  esti- 
mated pressure  at  its  base. 

At  this  point  another  most  important  fact  comes  in. 

31 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

The  steam  in  its  circuit  from  boiler  through  radiators 
and  piping  back  to  boiler  drops  in  temperature  very 
materially.  For  this  reason,  only  averages  are  consid- 
ered for  general  heating  deductions  when  determining 
radiator  surface  for  house-heating.  Unless  such  deduc- 
tions are  made  serious  errors  are  liable  to  occur. 

By  common  consent  the  trade  from  every  section 
of  the  country  seems  to  have  adopted  as  a  basis  in  hot- 
water  heating  a  drop  of  20  deg.  as  being  what  may  be 
safely  considered  the  drop  between  the  temperature 
of  a  hot-water  job  at  the  boiler  and  at  the  end  of  com- 
plete circuit.  Thus  if  the  water  leaves  boiler  at  180 
deg.  F.  they  expect  it  to  return  to  boiler  at  160  deg. 
and  they  figure  most  of  the  radiation  should  have  an 
average  temperature  of  170  deg.  [180°  +  160°  -f-  2  = 
170°].  Curiously  enough,  the  inevitable  drop  in  tem- 
perature of  the  steam  in  a  house-heating  job  seems  to 
be  pretty  generally  overlooked  by  the  average  steam- 
fitter.  But  it  is  there  just  the  same,  and  now  that 
definite  pressures  are  being  called  for  by  manufac- 
turers, owners  and  architects,  it  must  be  considered  at 
all  points. 

Those  American  authorities  who  have  written  on 
heating  have  quite  fully  indicated  this  loss,  but  in 
giving  out  rules  have  usually  covered  it  with  a  blanket 
under  the  guise  of  a  factor  of  safety,  but  this  factor,  as 
will  be  often  found  upon  analysis,  is  like  many  of  the 
rules,  only  strictly  applicable  within  a  limited  area 
of  territory  and  of  altitude. 


SECTION  V. 


The  following  table,  made  up  in  part  from  personal 
experiment  and  in  part  from  formulas,  gives  results 
that  can  probably  be  safely  relied  upon  for  house- 
heating  as  giving  the  average  or  mean  temperature 
in  radiators  of  cast-iron  3-column  construction  when 
the  temperature  at  the  boiler  is  as  stated  in  Column  A : 


A. 

Steam  Temperature 
at  Boiler 
Deg.  F. 

212 
211 
210 
209 
208 
207 
206 
205 
204 
203 
202 
201 
200 
199 
198 
197 
196 
195 
194 
193 


TABLE  E. 

B. 

Altitude  above 
sea-level 
In  feet. 

100 
500 
1,000 
1,500 
2,000 
2,500 
3,000 
3,500 
4,000 
4,500 
5,000 
5,500 
6,000 
6,500 
7,000 
8,000 
8,500 
9,000 
9,500 
10,000 

33 


C. 

Average  or  Mean 

Temp,  of  Radiator 

Deg.  F. 

201 
200 

198 

197.6 

196.7 

195.7 

194 

193.8 

192.8 

192 

191 

190 

189 

188 

187 

186 

185 

184 

183 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

In  figuring  the  heat  emitted  from  cast-iron  radiators, 
as  will  be  more  fully  explained  later,  the  temperature 
of  the  air,  which  is  to  be  maintained  at  a  given  tem- 
perature to  surround  the  radiator,  is  deducted  from 
the  average  temperature  of  the  heating  medium  in  the 
radiator;  and  it  is  upon  this  difference  that  nearly  all 
heating  calculations,  so  far  as  house-heating  is  con- 
cerned, are  based. 

With  this  explanation  it  is  easy  to  see  what  a  differ- 
ence altitude  creates.  There  are  towns  in  the  United 
States  much  more  than  10,000  ft.  above  sea-level,  but 
such  places  can  easily  ascertain  the  boiling  point  of 
water  at  their  altitudes,  and  they  will  find  the  average 
temperature  of  their  heating  medium  will  not  be  far 
from  95  per  cent  of  the  temperature  at  the  boiler. 

It  will  be  interesting  and  also  profitable  at  this  time 
to  consult  a  table  of  average  temperatures  at  boiler 
under  different  gage-pressures,  at  approximately  sea- 
level  altitude  and  the  average  mean  temperature  of 
3-col.  cast-iron  radiators  when  surrounded  by  air  in 
room  at  70  deg.  and  filled  from  boiler  at  stated  pres- 
sure. 

TABLE  F. 

Surrounding 
Air  70  deg.  F. 
70° 


Gage  Pressure 
Lb.  per  sq.  in. 

Temp, 
at  Boiler. 

Average  temp, 
in  Radiator. 

0 

212° 

201° 

1 

215 

204 

2 

219 

208 

3 

222 

211 

4 

224 

213 

5 

227 

216 

10 

239 

227 

15 

249 

237 

20 

258.7 

246 

25 

266.7 

254 

30 

273.9 

260 

K 


34 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

It  is  to  be  understood  that  the  above  table  is  given 
as  a  working  basis  and  no  claim  is  made  that  it  is  pre- 
pared with  laboratory  exactness. 

It  will  later  be  found  valuable  in  determining  what 
gage-pressure  will  be  required  to  comply  with  many 
of  the  terms  of  quite  recently  published  rules. 

It  will  also  prove  to  be  of  assistance  in  checking  up 
old-time  jobs  where  new  boilers  of  modern  ratings  are 
to  be  put  in  in  place  of  the  original  boilers.  Further- 
more, its  use  will  be  helpfully  manifest  in  many  ways 
as  our  study  of  cause  and  effect  in  heating  problems 
extends. 

This  table  is  for  sea-level  pressures  only.  At  higher 
altitudes  the  same  relative  difference  exists  that  are 
shown  between  steam  without  pressure  at  sea-level 
and  steam  without  pressure  at  different  altitudes  as  shown 
in  tables  C  and  D  of  altitude-temperature.  Page  29. 

I  have  deemed  it  well  to  take  this  part  of  the  heat- 
ing problem  up  before  going  into  the  loss  of  heat  from 
rooms  for  reasons  that  will  naturally  be  suggested  to 
the  student,  or  reader,  as  the  subject  develops. 

At  this  point  it  is  also  desirable  to  explain  the  heat 
unit  and  its  relation  to  the  noting  problem.  Many 
men  seem  to  be  afraid  of  the  term  heat-unit.  They 
might  as  well  be  afraid  of  the  term  inch,  when  speak- 
ing of  lineal  measure,  or  of  an  ounce,  or  pound,  when 
speaking  of  weight. 

If-you  should  weigh  one  pound  of  water  when  the 
thermometer  shows  its  temperature  to  be  62  deg.  F. 
and  then  apply  heat  to  the  water  until  the  thermome- 
ter reveals  one  degree  temperature-increase  or  63  deg. 
F.  and  if,  when  you  did  this,  you  were  at  the  sea-level 
and  the  water  was  open  to  the  atmosphere,  the  amount 

35 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

of  heat  employed  to  raise  that  pound  of  water  that  one 
degree  is  called  a  British  thermal  unit.  This  is  repre- 
sented by  the  letters  B.  t.  u.,  just  as  a  lineal  foot  is 
represented  by  the  letters,  ft.,  gallon  by  gal.,  a  degree 
of  temperature  by  deg.,  pound  by  lb.,  and  dollars  by  $. 

The  same  amount  of  heat  will  always  be  required  to 
raise  a  pound  of  pure  water  from  62  to  63  deg.  at  sea- 
level  at  atmospheric  pressure.  It  is  therefore  a  con- 
stant, something  to  be  depended  upon,  and  so  it  be- 
comes the  unit  or  one  item  by  which  all  combinations 
of  units  of  heat  can  be  measured. 

This  unit  of  heat  which  raises  one  pound  of  water 
one  degree  will  raise  one  pound  of  cast-iron  8  deg. ;  or 
it  will  raise  one  cubic  foot  of  air  from  zero,  about  50 
deg.  This  unit  of  heat  is  used  to  fix  what  is  known 
as  the  specific  heat  of  bodies.  Prof.  Carpenter  says: 
"Specific  heat  is  the  quantity  of  heat  required  to  raise 
the  temperature  of  a  body  one  degree,  expressed  in 
percentage  of  that  required  to  raise  same  amount  of 
water  one  degree,  or,  in  other  words,  with  water  con- 
sidered as  one.  Thus,  if  one  pound  of  iron  in  cooling 
eight  degrees  heats  one  pound  of  water  one  degree,  its 
specific  heat  is  %  =  0.125." 

The  specific  heat  of  air  is  0.238.  The  weight  of  a 
cubic  foot  of  air  at  zero  is  .0864  lb.  If,  therefore,  we 
multiply  the  weight  of  one  cubic  foot  of  air.  .0864  lb., 
by  the  specific  heat,  0.238,  we  shall  find  what  part  of  a 
heat  unit,  or  B.  t.  u.,  is  required  to  raise  one  cubic  foot 
of  air  at  sea-level  one  degree  F. 

Thus,  .0864  X  0.238  =  .0205632  B.  t.  u. 

To  raise  that  cubic  foot  of  air  from  zero  to  70  deg. 
will  require  70  times  as  much  or  1.439  B.  t.  u.  In  prac- 

30 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

tical  use,  1.44  B.  t.  u.,  or  1.5,  is  sometimes  used  by 
heating  engineers  in  estimating  losses. 

Now  we  can  understand  why  heat  is  measured  in 
B.  t.  u.,  and  why,  if  a  man  intends  to  do  good  work, 
he  desires  to  find  how  many  units  of  heat  are  lost  per 
hour  that  he  may  intelligently  proceed  to  replace  them. 

If  he  works  with  cubic  feet  of  air  instead  of  units  of 
heat  he  will  in  the  end  have  to  heat  the  air,  therefore 
it  is  better  to  stick  to  B.  t.  u.  from  the  start. 

Heat  has  two  values  or  qualities.  One,  we  can  de- 
scribe by  the  word  intensity,  and  the  other  by  the  word 
quantity.  The  intensity  of  heat  is  what  we  measure 
with  the  instrument  we  call  thermometer.  A  less  in- 
tense heat  we  may  call  zero,  and  a  more  intense  heat 
we  may  call  boiling  point,  but  it  is  evident  neither  con- 
dition of  intensity  has  any  especial  relation  to  quan- 
tity. A  small  quantity  at  zero,  or  at  boiling  intensity, 
has  no  different  measure  on  the  thermometer-measure 
of  the  same  article  than  a  great  quantity. 

The  intensity  of  heat  we  designate  temperature  and 
in  this  country  measure  it  zvith  a  Fahrenheit  thermome- 
ter. 

The  quantity  is  measured  by  the  number  of  heat  units 
present  in  the  body  when  it  shows  a  certain  intensity,  or 
temperature. 

Thus,  a  certain  quantity  of  heat  will  be  absorbed  by 
one  pound  of  water  before  it  will  show  an  increase  of 
one  degree  of  intensity.  This  gain  is  called  one  degree 
of  temperature. 

If  the  same  amount  of  heat  had  been  applied  to  one 
pound  of  iron  the  thermometer,  instead  of  registering 
an  increased  intensity  or  temperature  of  one  degree 
would  register  eight  degrees. 

37 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

It  is  evident  from  this  fact  that  the  amount  of  heat 
depends  upon  the  temperature  and  also  upon  the  capac- 
ity of  a  given  body  to  absorb  heat  without  shoiving 
any  increase  of  intensity  that  may  be  measured  by  a 
thermometer.  It  is  very  certain  therefore  that  under 
every  condition  the  nature  of  heat  is  different  from  tem- 
perature. 

The  amount  of  heat  which  is  absorbed  by  one  pound 
of  water  before  it  registers  an  increase  of  intensity,  or 
temperature,  as  this  will  hereafter  be  termed,  of  one 
degree  is  termed  its  "specific  heat."  Then,  when  at  sea- 
level  and  under  no  pressure  but  that  of  atmosphere, 
which  a  column  of  mercury  30  in.  high  balances,  the 
temperature  reaches  212  deg.,  the  entire  pound,  or 
other  quantity  of  water,  will  continue  to  absorb  heat 
without  any  increase  of  temperature  until  all  the  water 
has  been  evaporated  into  steam.  But  this  steam,  in 
cooling  to  a  lower  temperature  than  212  deg.,  emits 
heat  which  it  has  stored  or  absorbed  during  the  evapo- 
rating process  when  no  increase  in  temperature  was 
measured.  So  it  is  said  no  heat  was  lost,  although 
during  the  process  of  evaporating  the  pound  of  water 
a  large  amount  of  heat  had  been  applied  to  the  water 
of  which  the  thermometer  was  not  sensible.  This  heat 
which  the  stearr  gives  out  in  cooling  is  termed  "latent 
heat." 

It  will  be  seen  that  at  the  beginning  of  the  operation 
heat  was  absorbed  in  large  quantity  before  the  thermom- 
eter became  sensible  of  it,  and  at  the  evaporating  point 
a  still  greater  quantity  of  heat  was  absorbed  and  carried 
by  the  steam  of  which  the  thermometer  was  not  sensible. 

This  latter  heat  is,  however,  of  importance,  for  it 
contains  the  value  in  heat  units  of  the  whole  process 

38 


A     Practical    Manual    of     Steam    and    Hot-Water    Heating 

of  evaporation  and  has  been  shown  to  be  of  a  total  value 
above  zero  of  approximately  966  B.  t.  u.  The  temperature 
of  the  steam,  however,  is  only  212  deg.  To  get  the  total 
heat  involved  in  the  process  from  zero  to  212  deg.,  it  is 
evident  we  must  add  the  B.  t.  u.  of  sensible  heat  and 
the  B.  t.  u.  in  the  latent  heat,  then  212+966=1,178  B.  t. 
u.  employed  in  the  complete  process  from  zero  to  evap- 
oration. 

The  specific  heat  of  water  varies  slightly  at  different 
temperatures.  Therefore,  the  heat  contained  in  one 
pound  of  water  when  evaporated  from  different  temper- 
ature varies  slightly;  the  sensible  heat  above  zero  in- 
creases with  the  increased  intensity;  and  the  latent  heat 
grows  somewhat  less  relatively. 

At  a  temperature  of  240  deg.  in  the  water  at  point  of 
evaporation,  this  temperature  being  secured  by  putting 
the  water  under  pressure  greater  than  that  of  atmos- 
phere, the  sensible  heat  above  zero  becomes  equal  to 
241.31  B.  t.  u. ;  the  latent  heat  946  B.  t.  u. ;  total  1,187 
B.  t.  u.  A  cubic  foot  of  steam  at  212  deg.  weighs  .0379 
lb.,  while  at  240  deg.  it  weighs  .0634  Ib.  per  cu.  ft. 

As  pressure  is  increased  the  sensible  heat  increases  and 
the  difference  between  surrounding  air  of  a  stated  tem- 
perature and  the  surface  of  a  receptacle  like  a  radiate r 
holding  the  steam  stored  with  latent  heat  becomes 
greater,  and  so  more  heat  units  will  be  emitted  per 
square  foot  of  surface.  As  these  radiators  are  to  sup- 
ply the  heat  lost  from  n  room,  it  is  clear  that  the  size 
of  radiator  required  to  supply  a  certain  loss  will  be 
largely  governed  by  the  temperature  or  pressure  of  steam 
it  contains.  If  then  it  is  found  that  a  square  foot  of  such 
radiator  will  emit  one  and  six-tenths  B.  t.  u.  for  one 
degree  of  difference  of  temperature  in  one  hour,  and  that 

30 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

the  room  is  to  be  maintained  at  70  deg.,  it  being  zero  out- 
side, the  value  of  a  square  foot  of  radiation  is  easily 
found.  If  the  radiator  is  rilled  with  steam  at  212  deg.  the 
difference  between  room  and  radiator  is  212 — 70=142 
deg.,  and  if  each  of  these  142  deg.  calls  out  from  the  ra- 
diator 1.6  B.  t.  u.  latent  heat,  then  142X1.6=227  B.  t.  u. 
per  sq.  ft.  per  hr.  If,  on  the  other  hand,  the  water  had 
been  under  a  pressure  so  that  evaporation  did  not  occur 
until  a  temperature  of  240  deg.  had  been  attained  and  the 
radiator  is  filled  with  steam  at  this  pressure,  then  240 — 
70=170  deg.  difference;  170X1-6=272  B.  t.  u.  per  sq.  ft. 
per  hr.,  or  in  round  numbers  20  per  cent  difference  in 
size  of  radiator  required  to  emit  same  number  B.  t.  u. 

From  the  foregoing  it  is  evident  that  in  order  to  prop- 
erly size  radiators  to  give  off  the  needed  heat,  the  pres- 
sure under  which  the  job  is  to  work  must  be  determined 
and  the  entire  job  must  be  proportioned  to  that  pres- 
sure. 

In  order  to  do  this,  something  different  from  ratio- 
rules  will  be  needed  and  careful  attention  to  all  sources 
of  loss  and  suitable  provision  to  offset  them  must  be 
made.  The  following  table  gives  approximate  value 
per  square  foot,  per  hour,  of  radiators  at  different  tem- 
peratures. 

It  must  be  understood  that  Table  FF  is  based  on  aver- 
age conditions  as  they  are  found  and  is  calculated  for 
average  cast-iron  direct  radiators.  If  wrought-iron  pipe 
in  single  lengths  had  been  taken  instead  of  3-column 
cast-iron,  the  B.  t.  u.  per  sq.  ft.  per  hr.  would  be  in- 
creased materially,  especially  at  the  higher  temperatures. 
But  as  stated  previously,  this  book  is  for  those  who  do 
house-heating  principally.  Those  who  give  their  at- 
tention to  large  work  already  know  how  to  work  out 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

the  problem  of  heat-unit  delivery  from  wrotight-iron 
pipe  used  as  radiators,  and  which  gives  a  greater  heat- 
emitting  capacity  than  provided  for  in  the  present  table 
at  the  higher  temperatures. 

TABLE  FF. 

Temperature  of  Room  Throughout  this  Table,  70  cleg.  F. 
HOT  WATER  OR  STEAM. 

Temp. 

B.t.  u.  per  Dif.** 
Sq.  Ft.  per  Hr.*  Deg.  F. 

48  30 

64  40 

72  45 

80  50 

88  55 

.  96  60 

104  65 

'112  70 

120  75 

128  80 

136  85 

144  90 

152  95 

165  100 

182  110 

198  120 

215  130 

216  131 
220  138 
227  142 
232  145 
238  149 
243  152 
246  154 

*B.   t.    u.     Emitted   per   Sq.    Ft.   per   Hour   from   Average 
Direct  Cast-iron  Radiator,  3-col.  type. 

**Difference  Between  Radiator  and  Room  Deg.  F. 
41 


Boiler-Pres. 

Steam  in 

Radiator 

sure  Gage. 

Boiler. 

Deg.  F. 

.... 

110 

100 

.... 

120 

110 

.... 

125 

115 

.... 

130 

120 

.... 

135 

125 

.... 

140 

130 

145 

135 

.... 

150 

140 

.... 

155 

145 

.... 

160 

150 

165 

155 

.... 

170 

160 

.... 

175 

165 

.... 

180 

170 

.... 

185 

180 

.... 

200 

190 

.... 

210 

200 

212 

201 

2-lb. 

219 

208 

4-lb. 

224 

212 

5-lb. 

227 

215 

6-lb. 

229 

219 

7-lb. 

233 

222 

8-lb. 

234 

224 

A    Practical    Manual    of    Steam    and    Hot-Water    Heating 


10-lb. 

239 

227 

251 

157 

15-lb. 

250 

239 

270 

169 

20-lb. 

257 

249 

295 

179 

25-lb. 

267 

258 

310 

188 

30-lb. 

275.7 

266 

333 

196 

35-lb. 

280 

274 

347 

204 

Prof.  Allen  in  "Notes  on  Heating  and  Ventilation," 
page  52,  gives  the  value  of  2-column  cast-iron  radiators 
per  square  foot  per  degree  of  difference  as  1.455  for 
average  from  80  to  100  deg.  difference  and  1.635  as  aver- 
age from  110  to  170  deg.  difference  between  temperature 
of  radiator  and  room. 

J.  H.  Mills  and  Colonel  Greene,  of  Boston,  found  from 
extended  experiments  with  a  3-column  cast-iron  radiator, 
the  heat-unit  value  per  square  foot  per  hour  to  average  a 
trifle  over  1.65.  But  in  all  of  these  tests,  small  radiators 
and  short  pipe-runs  were  used.  In  practical  work  where 
long  runs  of  pipe  and  several  radiators  are  used,  1.6  B.  t. 
u.  per  square  foot  per  hour  is  all  that  can  safely  be  fig- 
ured for  3-column  radiators ;  1.65  for  2-column,  and  1.8 
for  single-column  cast-iron  radiators  per  degree  of  dif- 
ference between  heating  medium  in  the  radiator  and  air 
in  room  at  70  deg.  up  to  20-lb.  pressure. 


SECTION  VI. 


From  the  foregoing  tables  the  great  importance  of 
altitude  is  seen  when  reference  is  made  to  Tables  C  and 
D.  By  comparison  it  will  be  seen  that  a  rule  calling 
for  just  steam  temperature  in  radiator  at  sea-level  would 
never  work  out  for  use  at  higher  altitudes,  because  the 
steam  would  be  less  hot. 

For  instance,  a  house  at  New  York,  about  100  ft. 
above  sea-level,  requires  according  to  tabular  rule  500  sq, 
ft.  to  heat  it  to  70  deg.  when  it  is  zero  outside,  and  with 
steam  at  212  deg.  at  boiler.  This  would  yield  216  B.  t.  u. 
per  hr.  per  sq.  ft.  Then,  500X216=108,000  B.  t.  u.  per 
hr.  Supposing  the  same  owner  decides  to  duplicate  the 
house  on  some  of  the  hills  of  Pennsylvania  2,000  ft. 
above  sea-level.  His  steam  to  be  without  pressure  same 
as  at  New  York,  has  only  a  temperature  of  208  deg. ; 
the  average  temperature  of  the  radiator  is  only  197  deg. 
and  the  radiators  emit  but  203  B.  t.  n.  per  sq.  ft.  per  hr. 
The  500  sq.  ft.  give  out  500X203=101,500  B.  t.  u.,  a  dif- 
ference of  6,500  B.  t.  u.  per  hr.,  or  over  6  per  cent.  If 
he  had  put  in  533  sq.  ft.  instead  of  500,  the  two  jobs 
would  have  been  practically  the  same  if  the  wind  pres- 
sure was  the  same,  which  it  probably  would  not  be. 
Wind  pressure  must  surely  be  reckoned  with  in  looking 
for  heat  loss. 

When  this  question  of  altitude  is  considered,  of  what 
value  are  most  of  published  rules,  which  have  been 
calculated  for  sea-level  use  almost  without  exception, 
when  altitudes,  such  as  well-known  cities,  like  Albu- 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

querqtie,  N.  M. ;  Carson  City,  Nev. ;  Denver,  Colo. ;  Butte. 
Mont. ;  Ogden,  Utah ;  Pueblo,  Colo.,  and  many  others, 
are  reached,  all  of  them  about  5,000  ft.  above  sea-level? 
The  troubles  of  the  steam-fitter  who  attempts  to  follow 
sea-level  rules  of  heating  to  the  letter  fairly  overcome 
him  in  such  altitudes. 

Yet,  it  is  just  as  easy  to  procure  any  desired  result  at 
one  altitude  as  at  another  by  sticking  close  to  the  B.  t.  u. 
measure.  At  first  it  may  seem  to  be  a  little  more  trouble 
than  a  ratio-rule,  but  in  the  end  it  is  not,  as  will  be 
seen  later.  The  steam-fitter  must  intelligently  apply 
the  thermal-unit  loss  under  varying  conditions  encoun- 
tered in  detailed  measurements,  to  enable  him  to  suit- 
ably replace  this  loss  by  proportionate  radiation.  If  he 
thus  offsets  the  loss,  item  by  item,  he  will  be  called  back 
very  seldom  to  the  job  on  complaint  of  heating  efficiency 
below  the  requirements  of  contract. 

To  Determine  Amount  of  Heat  Loss  from  Walls. 

To  the  steam-fitter,  who  is  preparing  to  heat  a  house 
by  steam  or  hot-water  radiation,  it  is  especially  import- 
ant to  know  whether  the  whole  building,  or  certain 
rooms  in  building,  are  to  be  closed  off  from  heat  supply 
during  a  portion  of  each  day,  or  week,  through  the  heat- 
ing- season. 

o 

The  reason  why  it  is  important  is  hinted  when  spe- 
cific heat  is  defined.  The  walls  of  a  building,  whether 
brick,  stone,  wood  or  concrete  construction  possess, 
as  a  mass,  a  certain  specific  heat-value. 

In  accordance  with  the  definition  of  specific  heat, 
the  walls  of  a  building  absorb  a  certain  amount  of 
heat  before  the  thermometer  records  it.  This  amount 
of  heat,  or  some  portion  of  it,  the  steam-fitter  must 

44 


A    Practical     Manual    of    Steam    and     Hot-Water    Heating 

provide  from  his  boiler  and  the  radiators,  every  time 
the  walls  drop  from  the  established  constant  tempera- 
ture of  the  rooms.  This  constant  is  usually  70  deg. 
inside.  Experiment  has  shown  that  to  offset  the  spe- 
cific heat  of  walls  when  rooms  are  without  heat 
through  the  night  hours,  a  30-per  cent  increase  of 
radiator  surface  is  demanded  above  that  called  for 
if  rooms  are  kept  heated  day  and  night  and  if  rooms 
or  buildings  are  exposed  on  all  sides. 

If  the  building  or  room  is  only  slightly  exposed 
and  heated  during  day  only,  10  per  cent  will  usually 
offset  the  loss.  People  who  shut  the  heat  off  sleep- 
ing rooms  every  night,  and  want  to  leave  a  window 
open  in  addition,  require  from  20  to  40  per  cent  added 
for  that  particular  room,  according  to  the  extent  of 
wall  exposure  and  the  location  of  the  room.  If  the 
room  is  on  the  north  side  of  house  or  the  side  of 
prevailing  winter  wind  then  an  addition  of  40  per  cent 
will  not  be  excessive. 

During  daylight  hours  the  loss  of  heat  through  the 
walls  on  the  north  side  is  greater  per  square  foot  than 
from  the  south  side,  but  after  midnight  and  before  day- 
light, the  loss  is  equal  from  all  points  if  there  is  no 
wind,  something  that  very  rarely  happens. 

I  am  well  aware  that  steam-fitters,  as  a  whole,  have 
neglected  any  special  provision  for  extra  radiation  in 
rooms  not  steadily  heated,  but  that  does  not  annul 
the  fact  of  the  loss.  Nature,  when  she  created  "spe- 
cific heat,"  produced  the  condition ;  we  know  it  is 
there.  Why  not  meet  it? 

When  a  customer  shuts  the  heat  off  a  room  and 
permits  it  to  cool,  the  great  quantity  of  heat  in  those 
walls  is  entirely  dissipated  and  the  boiler  and  radi- 

45 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

ators  must  replace  it  each  time  the  room  is  heated. 
The  effect  is  the  same  on  the  heating  system  as  though 
the  room  had  been  increased  in  size.  This  will  become 
quite  clear  if  we  recall  that  the  amount  of  heat  neces- 
sary to  raise  five  pounds'  weight  of  masonry  one  degree 
in  temperature  would  raise  50  cu.  ft.  of  air  one  degree. 
Estimate  the  weight  of  a  wall  and  see  what  a  quantity 
of  air  would  be  heated  with  this  specific  heat  of  walls. 
Put  it  in  another  way.  Suppose  a  room  to  be  15x16x10 
ft.  with  a  total  cubic  content  of  2,400  cu.  ft.  The 
amount  of  heat  required  to  raise  the  walls  one  degree 
in  temperature  must  be  in  a  certain  relation  to  the 
heat  required  to  raise  the  cubic  contents  of  air  one 
degree.  Right  here  we  begin  to  find  the  advantage 
of  a  positive  measure  of  the  heat  by  B.  t.  u. 

We  have  already  seen  that  the  specific  heat  of  air 
is  .238,  that  a  cubic  foot  of  it  weighs  .0864  lb.,  and 
that  its  specific  heat  is  .0864  X  .238  =  .0205632  B.  t.  u. 

It  will  be  seen  that  50  cu.  ft.  of  air  would  be  raised 
one  degree  by  one  B.  t.  u.  .0205632  X  50  =  1. 

The  scientists  who  have  investigated  this  subject 
tell  us  that  the  amount  of  heat  required  to  raise  one 
pound  of  water  1°  will  raise  five  pounds  of  common 
brickwork  one  degree.  Builders  compute  that  a  cubic 
foot  of  common  brickwork  averages  in  weight  120  lb. 
If  one  solid  wall,  16x10  ft.,  is  exposed  there  would  be 
160  sq.  ft.,  and  if  one  foot  thick,  160  cu.  ft.  by  weight 
120  lb.  per  cu.  ft.  =  19,200  Ibs.  If  50  cu.  ft.  of  air  in 
the  room  is  raised  one  degree  by  one  unit  of  heat  it 
would  require  2,400  -f-  50  =  48  B.  t.  u.  to  raise  the 
cubic  contents  of  the  room  one  degree  and  48  X  70  = 
3,360  units  of  heat  to  raise  the  air  in  the  room  from 
zero  to  70  deg.  F.  If  one  heat  unit  will  raise  five 

46 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

pounds  of  masonry  one  degree  and  a  wall  exposed  to 
outside  air  weighs  19,200  lb.,  then  19,200  -f-  5  =  3,840 
B.  t.  u.  This  amount  must  be  furnished  every  time 
the  wall  cools  down  one  degree.  In  other  words,  it 
would  take,  in  case  illustrated,  more  heat  to  raise  the 
wall  one  degree  than  would  heat  the  cubic  contents  in 
air  from  zero  to  70  deg. 

When  a  room  is  brought  to  70  deg.,  however,  and 
this  temperature  maintained  for  12  hr.  out  of  the  24, 
and  then  permitted  to  cool  down  from  the  outside,  the 
loss  will  be  slow  and  not  all  of  the  specific  heat  of 
the  wall  is  dissipated  in  that  time.  But,  if  windows 
are  opened  so  that  the  heat  in  the  air  in  room  is  dissi- 
pated quickly,  the  loss  in  wall  is  greater,  because  the 
temperature  is  reduced  from  both  inside  and  outside 
influences. 

I  have  given  this  subject  of  the  specific  heat  of  walls 
a  quite  full  discussion  for  the  reason  that  it  has  not 
heretofore  received  the  attention  it  deserves,  especially, 
now  that  the  craze  for  sleeping  in  rooms  with  the  heat 
off  and  windows  open  is  spreading  so  rapidly. 

The  same  reasoning  holds  good  for  rooms  or  build- 
ings heated  only  at  long  intervals,  and  then  perhaps 
but  for  two  or  even  less  hours  of  steady  occupancy 
when  heated.  Such  rooms  usually  have  great  wall 
exposure  compared  to  cubic  contents,  and  it  often  re- 
quires from  24  to  48  hr.  of  continuous  firing  to  supply 
the  walls  with  their  specific  heat  before  the  ther- 
mometer begins  to  show  that  the  desired  temperature 
has  been  attained  by  the  air  itself.  If  the  heat  is 
withdrawn  only  a  few  hours  during  the  night,  the  loss 
from  the  constant  is  less  and  not  so  much  of  the  heat 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

* 

absorbed  by  the  walls  will  be  dissipated  as  would  be 
the  case  if  a  longer  period  of  non-supply  obtained. 

The  heat  absorbed  by  walls  in  a  hot  summer  day 
from  the  sun,  and  the  cooling'  down  of  the  same  walls 
at  night  furnishes  a  good  illustration  of  this  action 
when 'entirely  confined  to  natural  force  and  law. 

The  effect  of  wind  upon  heated  walls  can  be  studied 
with  profit  during  the  hot  summer  days.  The  illus- 
trations cited  show  the  necessity  of  the  fitter  knowing 
as  much  as  possible  in  regard  to  the  continuance  of 
hours  of  heat  to  be  maintained  per  day,  or  the  number 
of  days  per  week  that  a  continuous  heat  is  to  be 
maintained. 

It  is  the  habit  of  some  house-owners  to  permit  the 
heat  to  drop  out  entirely  from  some  rooms  for  long 
periods.  Others  let  the  fire  go  out  every  night.  These 
are  conditions  which  may  very  materially  affect  the 
amount  of  radiation  which  should  be  provided  and 
also  the  size  of  boiler  to  be  selected. 

The  German  government  has  had  very  exhaustive 
tests  made  of  this  phase  of  the  heating  question  and 
as  the  result  of  their  investigation,  German  engineers 
have  decreed  that  an  arbitrary  addition  to  radiation 
shall  be  made,  over  and  above  other  losses  to  be  pro- 
vided against,  of  10  per  cent  when  the  heating  is 
continued  during  the  day  only  and  closed  off  during 
the  night ;  30  per  cent  when  rooms  are  heated  during 
day  and  opened  to  outside  air  during  night;  50  per 
cent  when  long  periods  of  several  days  and  nights  pre- 
vail when  building  is  without  heat. 

The  loss  of  heat  through  average  walls,  per  square- 
foot  of  wall,  is,  of  course,  dependent  upon  the  material 
of  which  it  is  constructed,  the  manner  in  which  it  is 

48 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

constructed,  the  temperature  of  the  outside  air  and  the 
temperature  of  inside  air,  and  also  to  quite  an  extent  to 
the  force  and  velocity  of  the  wind  reaching-  outside 
surface  of  wall.  Most  elaborate  algebraic  formulas 
have  been  found  necessary  to  express  the  loss  of  all 
kinds  of  building  material,  but  for  the  needs  of  the 
"just  every-day  steam-litter,"  making  his  estimates  for 
average  house-heating  jobs,  the  average  results  of 
these  investigations  are  all  he  requires.  He  is  willing 
to  let  the  intricate  experiments  go,  if  he  can  have 
access  to  the  facts  ascertained. 

And  it  is  perhaps  well  that  that  is  his  attitude  if 
this  book  is  to  give  its  message  without  x.  y.  z.  formu- 
las. 

One  result  of  the  investigations  has  been  to  demon- 
strate that  in  practice  there  is  not  a  great  amount  of 
difference  in  the  loss  of  heat  from  walls  of  residences, 
whether  they  ar*e  constructed  of  wood,  brick,  stone  or 
concrete  per  square  foot  per  hour,  when  the  walls  are 
dry,  however  much  the  material  as  a  unit  may  vary 
in  its  capacity  to  conduct  or  absorb  heat.  This  is  ac- 
counted for  by  the  manner  of  construction :  for  in- 
stance, a  wooden  wall  boarded,  papered  and  clap- 
boarded  on  outside  of  studding  and  lathed  and  plas- 
tered inside  of  studding  has  a  valuable  air  space  the 
thickness  of  studs.  Air  is  a  poor  conductor  of  heat. 

A  brick  wall  as  usually  built  up  for  residences,  with 
plaster  often  laid  on  to  wall  itself,  will  conduct  as 
much  and  sometimes  more  heat  from  inside  to  out- 
side as  the  wooden  walls.  Therefore,  while  at  times 
there  arc  occasional  residence  walls  of  brick  or  stone. 
so  splendidly  constructed  as  to  require  different  per- 
centages of  loss  per  square  foot  than  the  average, 

49 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

such  exceptions  are  so  rare  in  this*  country  that  it  is 
safe  to  go  ahead  on  the  basis  that  average  loss  will 
apply  to  any  residence  which,  when  measured,  did  not 
disclose  the  fact  that  exception  should  be  made. 

At  this  time  no  addition  will  be  made  for  wind,  but 
in  the  final  summing-up  for  the  purpose  of  a  general 
rule  for  house-heating,  the  average  loss  per  hour  from 
wind  will  be  added  to  both  wall  and  window  surface. 
A  fair  average  for  square  foot  of  residence  wall  per 
hour  loss  in  B.  t.  u,  with  zero  temperature  outside  and 
70  deg.  inside,  can  be  reckoned  as  17  B.  t.  u.  per  sq.  ft. 
per  hour  in  a  dead  calm.  Very  thin  walls  will  lose 
more,  very  thick  walls  less.  As  an  approximate  guide 
the  following  table  based  on  brick  walls,  plastered  on 
inside,  air  zero  outside,  70  deg.  inside,  is  given.  It 
must  be  understood  the  loss  here  recorded  is  when 
there  is  no  wind.  The  force  or  velocity  of  wind 
changes  the  whole  proposition,  but  as  walls  often  are 
situated  so  that  no  wind  reaches  them  this  table  will 
be  useful. 


50 


SECTION  VII. 


TABLE  G. 

Approximate  loss  of  heat  through  walls  when  out- 
side air  is  zero.  Inside  air  70  deg.  per  sq.  ft.  per  hr.  in 
B.  t.  u.  Wall  plastered  on  one  side.  No  wind  blow- 
ing Building  continuously  heated  day  and  night. 

Thickness  of  B  t.  u.  Per  Sq.  Ft.  Per  Outside  Wall,  B.  t.  u. 

Wall.                Deg.  of  Difference.  Per  Sq.  Ft.  Per.  Hr. 

1  Brick                           0.357  25. 
iy2       "                               0.286  20. 

2  "  0.243  17. 
2^       "                                0.214                                        15. 

3  "  0.186  13. 

Inside  walls  often  divide  rooms  with  a  difference  of 
temperature  on  each  side.  Such  walls  require  atten- 
tion and  the  loss  through  them  supplied  by  radiation 
to  offset  this  loss.  The  following-  table  gives  a  fairly 
accurate  estimate  of  such  loss  per  square  foot  of  sur- 
face per  hour: 

TABLE  H. 

Approximate  loss  of  heat  through  partition  walls 
per  square  foot  per  hour  at  varying  differences  of  tem- 
perature between  rooms. 


Temperature 
Warm  Room. 

Temperature 
Colder  Room. 

Loss  Per  Sq.  Ft. 
Per  Hr.  B.  t.  u. 

70  deg. 

60  deg. 

3.5 

a 

50    " 

7. 

<t 

40     " 

10. 

" 

30     " 

13. 

(i 

20     " 

17. 

n 

10     " 

20. 

<i 

0     " 

23. 

51 


A    Practical    Manual    of    Steam    and    Hot- Water    Heating 

The  foregoing  tables  cover  walls  of  excellent  con- 
struction. Many  wooden  houses  are  constructed  very 
much  thinner  than  those  required  to  fill  conditions 
called  for  by  Tables  G  and  H.  Any  estimate  on 
wooden  walls  and  balloon  construction,  as  to  loss  per 
square  foot,  even  without  wind  blowing,  may  fall  far 
below  the  actual  loss.  I  offer,  however,  the  following 
as  a  fair  estimate  of  what  the  loss  in  B.  t.  u.  per  square 
foot  per  hour  may  be  from  such  construction,  it  being 
understood  the  walls  are  furred,  lathed  and  plastered 
on  the  inside : 

TABLE  I. 

Approximate  loss  of  heat  per  hour  in  B.  t.  u.  per 
square  foot  of  outside  wall  of  wooden  buildings,  bal- 
lon construction,  zero  outside,  70  deg.  F.  inside.  Heat 
continuous  day  and  night. 

B.  t.  u.  Loss 
from  Exposed 

Construction  of  Walls  Per 

Building.  Sq.  Ft.  Per  Hr. 

Crossboarded   and   Clapboarded 35. 

Crossboarded,  Thin  Paper  and  Clapboarded 25. 

Crossboardecl,  Double  Papered  and  Clapboarded        18. 

The  loss  of  heat  through  windows  next  requires  at- 
tention. 

This  particular  branch  of  the  heating  problem  has 
been  much  discussed  and  many  long  and  hard  words 
have  been  the  result. 

From  some  personal  experiments  and  much  study 
of  the  experiments  of  others,  I  conclude  that  it  makes 
a  considerable  difference  in  the  heat  loss  through  glass 
whether  the  glass  is  wet  or  dry.  It  also  makes  a  very 
marked  difference  how  hard  the  wind  is  blowing  when 

52 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

tests  of  loss  through  windows  installed  in  a  building- 
are  made,  and  some  difference  how  high  the  window 
is,  in  comparison  with  total  height  of  room. 

Nearly  every  scientist  who  has  experimented  on  loss 
of  heat  through  glass  has  determined  the  loss  per 
square  foot  per  hour  to  be  near  one  B.  t.  it.  per  degree 
of  difference  between  the  temperatures  of  the  two 
sides. 

Peclet,  whose  experiments  and  formulas  are  the  real 
foundation  of  the  modern  science  of  heating,  found 
very  considerable  difference  in  loss  per  square  foot 
when  room  was  70  deg.  inside  and  zero  outside,  when 
the  windows  were  of  different  heights. 

The  following  table  reduced  to  B.  t.  u.  from  Peclet's 
data  makes  the  point  quite  clear: 

TABLE  J. 

Loss  per  square  foot  per  hour  from  windows  with 
70  deg.  difference  in  temperature. 

Ft.  In.     Ft.  in.       Ft.  In.     Ft.  In.       Ft.  In. 

Height  of  Windows..  3367        10     0      13     3        16     3 

Loss  in  B.  t.  u.  per 
Deg.  Diff.  Tem- 
perature    0.98  0.945  0.93  0.92  0.91 

The  German  scientists  practically  agree  that  the 
average  window-loss  is  .97  B.  t.  u.  per  square  foot 
per  degree  of  difference  per  hour,  and  then  comes  the 
German  government  with  the  demand  that  windows 
be  figured  to  lose  1.09  B.  t.  it.  per  degree  of  difference. 

This  demand  on  the  part  of  the  German  government 
seems  to  cast  a  doubt  upon  the  correctness  of  .97  B. 
t.  it.  But  add  to  .97  the  increase  because  of  average 
wind  velocity,  as  will  be  fully  illustrated  in  the  dis- 

53 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

cussion  upon  wind  pressure,  and  it  will  be  seen  that 
the  .97  has  been  accepted  as  correct.  Assuming  the 
average  winter  wind  to  be  at  rate  of  18  ft.  per  sec.,  or 
12.3  miles  per  hour,  and  allowing  one  per  cent  per 
mile  velocity  addition  for  loss  from  window  because 
of  this,  and  .97  +  12.3-10  per  cent  =  1.09,  which  is 
what  the  German  government  calls  for.  In  other  words, 
they  call  for  the  loss  from  windows  under  average  work- 
ing conditions,  not  laboratory  conditions.  It  will  at 
once  be  seen  that  the  government  is  correct.  In  the 
tables  on  the  loss  of  heat  from  walls  and  windows  to 
be  found  later  in  the  discussion,  the  various  differences 
created  by  the  wind  will  be  considered  quite  fully. 


TO    DETERMINE    AMOUNT    OF    HEAT-LOSS 
FROM  ROOMS  IN  BUILDINGS. 

Effect  of  Wind  on  Loss  from  Walls  and  Windows. 

It  requires  no  long  argument  to  establish  the  fact 
that  a  room  continually  exposed  to  a  strong  wind  will 
cool  from  a  given  temperature  above  that  of  outside 
air  to  that  of  outside  much  more  quickly  than  one  not 
so  exposed,  but  otherwise  under  the  same  conditions. 
It  is  in  order  to  understandingly  figure  for  such  addi- 
tional loss  that,  when  measuring  the  building,  special 
note  is  made  of  the  direction  of  prevailing  winds. 

It  is  a  self-evident  fact  that  the  velocity  of  the  wind 
varies  many  times  in  a  day  and  the  best  that  can  be 
done  is  to  work  upon  average  conditions,  and  make 
special  provision  for  conditions  beyond  the  normal.  It 
is  also  evident  that  such  a  very  important  factor  can- 
not be  overlooked  in  designing  a  heating  plant. 

The  average  velocity  of  the  wind  not  only  varies 

54 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

from  day  to  day,  but  varies  in  different  sections  of  the 
country,  and  even  in  different  portions  of  quite  small 
towns. 

In  years  past,  architects  and  owners  have  not  been 
in  the  habit  of  specifying  any  special  boiler-pressure, 
or  temperature,  contenting  themselves  with  the  gen- 
eral requirement  of  70  deg.  in  room,  or  some  specified 
room-temperature.  But  within  a  short  time,  architects 
and  owners  have  been  demanding  that  heating  jobs 
shall  give  all  sorts  of  temperatures  in  rooms  and  that 
they  shall  prevail  whe;i  the  temperature  at  boiler  is 
not  to  exceed  180  deg.  in  a  hot-water  boiler,  or  2-lb. 
gage  pressure  on  a  steam  job,  and  a  final  settlement 
for  the  job  is  often  refused  unless  the  requirements 
both  as  to  room  and  boiler  temperatures  are  explicitly 
complied  with. 

Under  these  changed  conditions  it  does  not  seem 
wise  to  overlook  a  factor  which,  if  not  provided  for, 
may  cause  the  expending  of  a  considerable  sum  of 
money  and  many  hours  of  time  in  adding  sections  to 
radiators  in  order  to  comply  with  contract-terms  in 
rooms  on  north  side  of  a  building  or  at  points  espe- 
cially swept  by  winter  wind. 

Here  again  the  question  of  altitude  presses  upon 
our  attention.  This  time  not  only  the  altitude  above 
sea-level,  but  the  altitude  of  the  radiator  above  the 
boiler,  which  will  affect  the  temperature  of  the  steam 
or  water  in  the  radiator.  This  will  be  more  fully  dis- 
cussed under  the  question  of  piping. 

In  regard  to  wind,  a  very  serious  discussion  is  de- 
manded. The  old  rules  are  utterly  valueless  as  a  guide 
to  the  conscientious  steam-fitter  who  wishes  to  do 
good  work. 

55 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

The  books  on  the  question  as  they  affect  the  steam- 
fitter  are  singularly  silent  on  the  question,  and  it  is 
deemed  well  to  discuss  it  quite  freely  at  this  time. 

The  Encyclopedia  Brittanica,  Vol.  16,  page  157, 
sorts  winds  as  "Polar  or  cold  winds  which  blow  from 
N.  W.,  N.,  N.  E.,  and  E. ;  and  Equatorial,  or  warm 
winds,  as  those  from  S.  E.,  S.,  S.  W.  and  W.,"  and 
states  that  the  "polar  or  cold  winds  have  a  greater 
mean  velocity  of  over  one  mile  per  hour  than  the 
equatorial  winds." 

As  fitters  often  have  occasion  to  figure  for  friends 
or  others  in  a  section  remote  from  their  own  locality, 
in  a  general  way  it  can  be  said  that  the  prevailing- 
winter  winds  in  the  United  States  and  Alaska  are  as 
follows :  Alaska,  N.  E. ;  New  England  States,  N.  W. ; 
the  Atlantic-Coast  States,  as  far  south  as  North  Caro- 
lina, N.  W. ;  South  Carolina  and  farther  south  on 
coast,  W.  The  great  midland  sweep  of  states  from 
the  Great-Lake  region  to  western  Texas,  but  east  of 
the  Rocky  Mountains,  present  an  irregular  division 
of  prevailing  winter  winds,  which  can  be  said  to  be 
caused  by  two  great  regions  of  high  barometer-pres- 
sure, one  in  the  southeast  section,  the  other,  and 
larger  of  the  two,  having  its  center  near  Utah. 

Between  these  there  is  interposed  a  region  of  lower 
barometer-pressure,  extending  from  northeastern  Illi- 
nois to  southwestern  Texas.  On  the  western  line  of 
this  irregular  line  the  prevailing  winter  winds  seem  to 
be  from  the  northwest,  but  toward  the  eastern  edge 
of  it  they  become  West,  W.  S.  W.,  S.  W.,  becoming 
N.  W.  as  they  reach  the  mountains  of  North  Carolina. 

Alone:  the  coast  of  the  Gulf  of  Mexico  and  south 

o 

56 


A    Practical     Manual    of    Steam    and     Hot-Water    Heating 

of  the  irregular  line  mentioned  the  prevailing  winter 
winds  seem  to  be  from  the  northeast. 

The  Pacific-Coast  States  and  the  territory  west  of 
the  Rocky  Mountains  present  a  great  many  rather 
sudden  changes  in  direction  of  prevailing  winds  ;  from 
N.  at  Fort  Yuma,  Cal.,  to  nearly  S.  at  other  points. 
The  variation  is  so  marked,  even  within  compara- 
tively short  distances,  that  local  conditions  should  be 
ascertained  before  attempting  to  figure  for  Pacific- 
Coast  heating  jobs  in  regard  to  exposure  to  wind. 

The  following  table  shows  something  of  the  force 
of  wind. 

The  descriptive  names  may  not  meet  with  the  ap- 
proval of  my  readers,  but  they  can  choose  names  to 
please.     It  is  the  feet  per  second  and  the  miles  per 
hour   that   does   the   heat-transporting  act. 
TABLE  K. 

Force,  velocity  and  pressure  in  pounds  per  square 

foot  of  wind.  Pressure  in  Ib. 

Velocity  Miles       per  sq.  ft.  of 

Perceptible  Force.                               per  hour.  Surface. 

Just  perceptible  2  .02 

Gently  pleasant    4  .08 

Light  breeze   10  .5 

Fair    breeze    12  .71 

Good  breeze   35  1.2 

Stiff   breeze    20-25  2.1-3 

Strong   breeze    30  4.5 

High    wind    35  6. 

Very    high    wind 40  8. 

Very    strong    wind 45  10. 

Wind  storm    50-55  12-15 

Violent    Storm     60-65  18-21 

Gale 70-75  24-27 

Hurricane    80  37. 

Violent  hurricane 100  49. 

57 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

It  is  probable  that  the  winter  winds  of  the  country 
over  will  average  12^  miles  per  hr.,  or  22  ft.  per  sec., 
with  a  pressure  of  perhaps  12  oz.  per  sq.  ft.  of  exposed 
surface. 

The  Encyclopedia  Britannica  (Vol.  XVI,  p.  125), 
states  that  "the  velocity  of  wind  on  the  open  sea  is 
considerably  in  excess  of  that  near  land  .  .  .  650 
daily  observations  on  the  open  sea  give  a  mean  hourly 
velocity  of  17^2  miles,  whereas  552  observations  near 
land  give  a  velocity  of  only  12J/2  miles  per  hour." 

The  German  engineers  figure  on  a  shade  less  than 
12.5  miles,  about  12.3  miles  per  hr.  in  the  open  coun- 
try. In  this  country  there  are  many  sections  where 
15  or  20  miles  an  hr.  would  not  be  excessive. 

Here  again  altitude  cuts  a  very  important  part. 

It  is,  of  course,  out  of  the  question  to  prepare  a 
table  that  shall  be  exact  as  an  offset  for  wind-pressure, 
but  a  fairly  safe  average  when  the  room  is  to  be  main- 
tained at  70  deg.  and  outside  temperature  is  32  deg. 
or  below  is  to  increase  the  total  loss  in  B.  t.  u.  from 
all  other  sources  from  the  wind-swept  rooms  from 
one  to  one  and  one-half  per  cent  for  each  mile  of 
wind-velocity.  Thus,  if  a  sheltered  position  s.  re- 
duced the  average  wind-velocity  that  it  was  not  above 
10  miles  per  hr.,  add  10  per  cent;  if  so  exposed,  be- 
cause of  altitude  or  other  cause,  that  the  average 
wind  was  15  to  20  miles  per  hr.,  add  from  20  to  30 
per  cent. 


58 


SECTION  VIII. 


The  discussion  in  regard  to  loss  of  heat  from  walls  can 
be  summed  up  as  in  Table  L. 

TABLE  L. 

Table  Showing  Probable  Loss  Per  Sq.  Ft.  Per  Hr.  in  B.  t.  u. 
from  Average  Well-Built  Residence- Wall  Surface  When  Rooms 
are  at  70  Deg.  F.  Outside  Air  Zero.  With  various  Wind 
Velocities.  Rooms  Not  Over  12  ft.  High  and  Continuous  Heat 
Maintained  Day  and  Night. 

Loss  in  B.  t.  u.  Per  Sq.  Ft.  Per  Hr. 


,  

Plastered. 

No           2  Miles        5  Miles 

10  Miles 

Thickness  of  Wall. 

Wind        Per  Hr.       Per  Hr. 

Per  Hr. 

1        Brick    .  . 

25              25  5               26  25 

27.50 

2        Brick     

17.             17.34             17  85 

18.70 

2^     Brick    

15.             15.30             15.75 

16.50 

3        Brick 

13              13  26             13  65 

14.30 

3l/2     Brick 

11              11  02             11  55 

12.10 

\A7in  f\  \7*p1rir*i'f"i  PC 

Average  Winter  Wind, 

15  Miles           20  Miles 

30  Miles 

12*/2  Miles  Per  Hr. 

Per  Hr.             Per  Hr. 

Per  Hr. 

1                 28.12 

28.75                  30.00 

32.50 

2                  19.12 

19.55                  20.40 

22.10 

lY*              16.87 

17.25                   18.00 

19.50 

3                   14.63 

14.95                   15.60 

16.90 

3l/2               12.38 

12.65                   13.20 

14.30 

To  use  this  table,  multiply  total  net  square  feet  of  ex- 
posed wall  by  factor  representing-  wind-velocity  required. 
For  example — A  wall  equivalent  to  a  2-brick  wall  has, 
say,  125  sq.  ft.  of  net  exposed  surface.  We  are  required 
to  estimate  the  probable  loss  per  square  foot  per  hour 
and  total  loss  per  hour,  wind  at  average  winter-velocity  of 
12JA  miles  per  hour.  Room  70  deg.,  outside  air  zero. 
Heat  continuous. 

59 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

Under  12*/?  miles  we  find  probable  loss  per  sq.  ft, 
19.12  B.  t.  ti.  Total  net  wall,  125  X  19.12  =  2390  B.  t.  it. 
per  hour  loss  from  the  wall.  The  window  loss  will  be 
found  from  Table  M. 

TABLE  M. 

Loss  of  Heat  in  B.  t.  u.  from  Window  Surface  Per.  Sq.  Ft.  Per 
Hour,  for  Each  Degree  of  Difference  Between  Temperature  of 
Rooms,  and  Temperature  of  Outside  Air,  Varying  Velocities  of 
Wind.  Room  Not  Over  12  Ft.  High.  Heat  to  be  Continuous 
Day  and  Night. 

Description  —Wind  Velocities  Per  Hr. — 

of  No  Wind  Wind 

Glass  Wind.  2  Miles  5  Miles. 

Single  thick  co.r.mon .97  .99  1.02 

Double    window 45  .46  .47 

Single   skylight 1.09  1.11  1.14 

Double    skylight 49  .50  .51 

— Wind  Velocities  Per  Hour — 

Wind  Ave.  Winter  W'ind        Wind  Wind 

10  Miles.  r?,y2  Miles.  15  Miles.  20  Miles. 

1.07  1.09  1.17  1.26 

.50  .51  .54  .58 

J.20  1.22  1.30  1.41 

.54  .55  .59  .63 

The  use  of  this  table  is  clear.  If  with  an  average  wind  of  12^ 
miles  per  hour  one  square  foot  of  window  loses  1.09  B.  t.  u.  per 
degree  of  difference,  then  at  70  deg.  difference  the  loss  will  be 
1.09X70  =  76.30  per  hour  and  100  sq.  ft.  would  lose  76.30  X100= 
7630  B.  t.  u.  per  hour. 


The  window  surface  is  one  of  the  great  sources  of 
heat-loss.  As  already  explained,  the  scientists  are  fairly 
well  agreed  upon  the  loss  in  dead  calm  as  .97  B.  t.  u. 
per  sq.  ft.  per  degree  of  difference.  If  the  outside  was 

60 


A     Practical    Manual    of    Steam    and    Hot-Water    Heating 

zero  and  inside  70  deg.,  the  difference  would  be  70 ;  then 
.<)v  X  70  — 67.9 -P>.  t.  ii.  per  hour  per  sq.  ft.  of  window. 
If  the  window  had  25  sq.  ft.  of  surface,  the  total  loss  -for 
the  window  "in  a  dead  calm"  would  be  1697*^  B.  t.  u., 
but  with  wind  blowing-  this  loss  is  increased  as  seen  by 
Table  M,  calculating  on  an  average  winter  rate  of  I%y2 
per  cent  to  1907^  B.  t.  u. 

In  order  that  those  who  do  not  care  to  take  the  time 
to  make  up  a  table  of  loss  per  square  foot  of  window 
surface  when  the  usual  conditions  required  are  called 
for,  viz.,  zero  outside,  70  deg.  inside,  wind  normal,  or, 
at  an  average  of  12^  miles  per  hour,  the  following 
Table  N  will  be  of  advantage. 

Any  other  temperature  than  70  deg.  and  any  wind 
velocity  other  than  the  average,  can  easily  be  made  use 
of  by  multiplying  the  required  factor  in  Table  M  by  re- 
quired temperature.  Desired  the  heat  loss  from  a  win- 
dow when  room  is  60  deg.  inside,  outside  20  deg. ;  wind, 
5  miles  per  hour.  The  factor  per  degree  of  difference 
by  table  is  found  under  5  miles  to  be  1.02  B.  t.  u.  per  sq. 
ft.  The  difference  between  60  and  20  =  40.  Then,  1.02 
X  40  --  408-10  B.  t.  u.  In  practice  this  would  be 
called  41. 

TABLE  N. 

Showing  probable  loss  per  sq.  ft.  of  surface  of  win- 
dow per  hour  with  air  at  zero  outside,  70  deg.  F.  inside. 
Normal  or  average  wind  velocity  of  12^  miles  per  hour. 

Description                                   Av.  Win.  Wd.  Prob.  Loss  Per 

of  Window.                                       Vel.  Per  Hr.  Sq.  Ft.  Per  Hr. 

Single    thickness,    common 12^2  miles  76.3 

Double   window .  35.7 

Single    skylight 85.4 

Double     skylight '    38.5 

(51 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

It  may  be  found  useful  to  have  a  table  giving  in  square 
feet  and  fractions  thereof  the  area  of  the  usual  windows 
found  in  buildings,  and  for  this  purpose  Table  N-l  is 
given : 

TABLE 

Glass  Surfaces 
Areas  in  Square  Feet  and 


Ft.  In. 

F.In. 

Ft.  In. 

Ft.  In. 

Ft.  In. 

Ft.  In. 

Ft.  In. 

1     8 

1  10. 

2     0 

2     4 

2     6 

2     8 

3     6  

5.81 

6.42 

7. 

8.17 

8.75 

9.33 

3  10  

6.36 

7.03 

7.67 

8.94 

9.58 

10.22 

4     2  

6.94 

7.64 

8.33 

9.72 

10.42 

11.11 

4     6  

7.50 

8.25 

9. 

10.49 

11.25 

12. 

4   10  

8.05 

8.86 

9.67 

11.28 

12.08 

12.88 

5     2  

8.61 

9.47 

10.33 

12.05 

12.92 

13.77 

5     6  

9.16 

10.08 

11. 

12.83 

13.75 

14.66 

5  10  

9.72 

10.69 

11.67 

13.61 

14.58 

15.55 

6     2  

10.27 

11.30 

12.33 

14.39 

15.42 

16.44 

6     6  

11.91 

13. 

15.16 

16.25 

17.33 

6   10  

13.67 

15.94 

17.08 

18.22 

7     2  

16.72 

17.92 

19.11 

7     6  

18.75 

20. 

7  10  

20.88 

8     2  

8     6  

8   10  

To  find  area,  note  where  the  height  as  given  at  the  left 
side  of  table  intersects  with  width  as  given  at  top.  For 
example :  The  area  of  a  5  ft.  10  in.  x  2  ft.  8  in.  window 
is  15.55  sq.  ft. 

We  now  come  to  the  consideration  of  the  matter  of 
leakage  from  rooms  through  other  sources  than  walls 
and  windows. 

Doors  naturally  present  a  source  of  intermittent  loss 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 


that  can  only  be  covered  with  some  general  factor  of 
safety,  but  outside  doors  should  be  specially  considered 
as  certainly  as  windows. 


N-l. 

in  Windows. 

Fractions  of  a  Foot. 


Ft.  In. 
210 
9.92 

Ft.  In. 
3 
10.5 

Ft.  In. 
3    2 
11.08 

Ft.  In. 
3      4 

Ft.  In. 
3      6 

Ft.  In. 

3      8 

Ft.  In. 
3    10 

Ft.  In. 
4      0 

10.86 

11.5 

12.14 

12.78 

11.80 

12.5 

13.19 

13.89 

14.58 

12.75 

13.5 

14.25 

15. 

15.75 

16.50 

13.69 

14.5 

15.30 

16.11 

16.92 

17.72 

18.52 

14.64 

15.5 

16.36 

17.22 

18.08 

18.94 

19.80 

20.66 

15.58 

16.5 

17.41 

18.33 

19.25 

20.16 

21.08 

22. 

16.52 

17.5 

1.8.47 

19.44 

20.42 

21.38 

22.36 

23.33 

17.47 

18.5 

19.52 

20.55 

21.58 

22.60 

23.63 

24.66 

18.41 

19.5 

20.58 

21.66 

22.75 

23.83 

24.91 

26. 

19.36 

20.5 

21.63 

22.77 

23.82 

25.05 

26.19 

27.33 

20.30 

21.5 

22.69 

23.88 

25.08 

26.27 

27.47 

28.66 

21.25 

22.5 

23.75 

24.99 

26.25 

27.50 

28.75 

30. 

22.19 

23.5 

24.80 

26.11 

27.46 

28.72 

30.02 

31.33 

23.13 

24.5 

,25.85 

27.22 

28.58 

29.94 

31.30 

32.66 



25.5 

26.91 

28.33 

29.75 

31.16 

32.58 

34. 

27.97 

29.44 

30.92 

32.38 

33.86 

35.33 

It  is  the  practice  of  some  to  consider  doors  which  open 
directly  to  room  as  having  same  loss  as  windows,  and  it 
is  not  a  bad  practice.  Yet  some  doors  are  hardly  so 
productive  of  loss  as  that,  and  for  quite  careful  esti- 
mators the  losses  shown  in  Table  O  have  been  found  to 
be  quite  exact  for  the  average  machine-made  doors. 
This  table  can  be  used  also  for  tongued  and  grooved 
board  walls  if  they  are  perfectly  matched  and  tight. 

63 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

TABLE  O. 

Probable  loss  per  hour  per  degree  difference  of  tem- 
perature from  outside  doors  in  B.  t.  u.  per  sq.  ft.  of 
surface : 

Thickness.  Soft  Wood.  Hard  Wood. 


*/2 

in  

58  

72 

H 

in  

49  

65 

i 

in  

43  

GO 

154 

in  

38  

56 

V/2 

in  

33  

52 

2 

in  

30  

,  45 

2Y2 

in  

26  

41 

3 

in  

.  .23.. 

.  .37 

Glass  in  doors  should  be  figureed  with  glass  surface  of 
room. 

One  very  considerable  source  of  leakage  is  found  to 
be  that  from  fireplaces. 

This  loss  can  be  more  nearly  measured  than  from 
many  of  the  minor  sources,  such  as  loose-fitting  doors 
and  windows,  and  semi-direct  openings,  such  as  arise 
from  careless  carpenter  or  mason  work  in  fitting  door 
and  window  frames.  These  are  sometimes  so  badly 
fitted  as  to  cause  very  serious  heat-loss.  Usually  a  care- 
ful "measurer-up"  will  discover  such  conditions  and  note 
them,  but  when  figuring  from  plans  it  is  always  safe  to 
put  in  a  factor  of  safety  for  this  and  similar  loss.  This  is 
usually  covered  in  the  times-per-hour  provision  made  for 
change  of  air.  Wooden  and  concrete  houses  quite  often 
are  so  carelessly  constructed  in  this  respect  that  no  mis- 
take is  made  in  allowing  for  three  or  even  four  changes 
per  hour  of  total  cubic  contents  of  air. 

Houses  with  a  big  reception-hall,  which  may  also  be 
the  living  room  and  usually  with  a  big  fireplace,  is  a  room 
to  call  for  most  critical  examination.  The  fireplace  throat. 
even  if  it  has  a  good  damper,  that  can  be  closed,  had  best 

64 


A     Practical    Manual    of     Steam    and    Hot-Water    Heating 

be  considered  as  always  open,  and  the  rush  of  air  through 
such  an  opening  is  large. 

Such  fireplaces  often  have  an  opening  of  full  144  sq. 
in.,  and  it  is  of  the  utmost  importance  to  find  out  about  it. 

Old  houses  with  fireplaces  in  the  rooms  quite  often 
have  no  provision  for  shutting  off  the  fireplace  draft  ex- 
cept a  loose-fitting  front. 

These  fireplaces  and  other  minor  leaks,  each  perhaps 
small  in  itself,  when  all  collected  as  one  item,  quite  often 
produces  a  loss  in  B.  t.  u.  per  hour,  several  times  the 
amount  that  would  be  required  to  maintain  the  cubic 
volume  of  air  of  the  room  itself  at  a  given  temperature, 
say,  70  deg.  for  an  hour. 

This  can  be  illustrated  by  a  very  common  condition 
found  in  residences.  In  a  room,  for  example,  14x16x10 
ft.,  containing  2,240  cu.  ft.,  is  found  a  fireplace  with  a 
throat,  opening  direct  to  a  chimney,  which  is  likely  a 
12xl2-in.  chimney  or  larger,  and  at  least  30  ft.  high. 
This  fireplace  throat  may  be  3x12,  4x12,  or  even  6x12  in. 

When  the  temperature  of  the  room  is  at  70  deg.  F.  and 
the  external  air  is  at  30  deg.  F.,  the  mean  temperature 
of  the  chimney  with  the  air  from  room  going  through 
it  might  be  50  deg.,  or  30  deg.  in  excess  of  outside  air. 

At  this  difference  the  3x12  fireplace  throat  opening 
into  chimney  would  discharge  66j4  cu.  ft.  of  air  per  min. 
from  the  room  to  chimney,  or  3,975  cu.  ft.  per  hr.  This 
gives  1,735  cu.  ft.  per  hr.  to  be  heated  more  than  the 
cubic  contents  of  room  specified,  or  within  505  cu.  ft.  of 
twice  the  cubic  contents. 

If  the  chimney-throat  was  6x12  in.,  the  air  moved 
under  conditions  named  would  be  132^2  cu.  ft.  per  min., 
or  7,950  cu.  ft.  per  hr.,  nearly  four  times  the  cubic  con- 
tents. Think  of  trying  to  solve  a  fireplace  problem  by 
any  ratio-rule  based  upon  cubic  contents! 

65 


SECTION  IX. 

The  Table  P  is  given  as  showing  the  probable  quan- 
tity of  air,  in  cubic  feet,  passing  through  a  flue  having 
a  sectional  area  of  one  square  foot,  like  a  12x12  chim- 
ney, at  various  temperatures  of  difference  and  height. 

TABLE  P. 

Showing  probable  amount  of  air  discharged  per  minute  in 

natural 


Height  of 
Flue  in  feet. 

20  . 

5deg. 
108 

10  deg. 
153 

Excess  of 
15  deg. 
188 

Temperature 
20  deg. 
217 

25 

121  * 

171 

210 

242 

30  . 

133 

188 

230 

265 

40  

153 

217 

265 

306 

50  

171 

242 

297 

342 

It  will  be  found  easy  to  calculate  fireplace  loss  ap- 
proximately close  from  above  table.  The  height  of  resi- 
dence chimneys  above  fireplace  rarely  exceeds  30  ft.  and 
the  average  temperature  of  flue,  unless  it  receives 
warmth  from  some  other  flue  in  the  stack,  rarely  ex- 
ceeds 50  deg. 

If  some  other  flue,  as  the  boiler-flue  or  kitchen-flue,  is 
alongside  the  fireplace  flue,  the  temperature  of  flue  may 
be  as  high  as  150  deg.  at  times  above  external  air. 

The  cubic  feet  in  table  is  per  minute.  To  find  hourly 
discharge  multiply  by  60.  To  find  loss  frorrT  fireplace 
throat,  divide  hourly  loss  by  fractional  portion  of  square 
foot  corresponding  to  throat-opening.  Suppose  a  fire- 

66 


A    Practical    Manual    of     Steam    and    Hot-Water    Heating 

place  throat  to  be  4x12  in.=  48  sq.  in.  Then  48/144  of 
hour  loss  under  conditions  existing  as  shown  from  use  of 
table,  would  be  the  B.  t.  u.  loss  per  hour  from  fireplace 
as  already  illustrated.  Thus,  with  external  air  at  30  deg. 
and  chimney  50  deg.,  the  difference  being  20  deg.,  the 
loss  per  sq.  ft.  is  probably  265  cu.  ft.  per  minute.  An 
opening  3x12  in.  equals  36  sq.  in.  and  36/144  of  265  = 

TABLE  P. 

cu.  ft.    from  a  warm  room  through  a  12xl2-in.  Chimney  by 
draft. 

of  Air  in  Flue  Above. External  Air. 

25  deg.          30  deg.          40  deg.  50  deg.         100  deg.         150  deg. 


242 

265 

306 

342 

271 

297 

342 

383 

541 

663 

297 

325 

375 

419 

593 

726 

342 

375 

431 

484 

684 

838 

383 

419 

484 

541 

765 

937 

66.25  per  min. ;  66.25  X  60  =  3,975  B.  t.  u.  per  hour  as 
previously  stated. 

To  still  further  emphasize  the  great  importance  of 
fireplace  openings,  compare  the  case  of  window-loss  with 
the  fireplace  thus  considered.  A  window  under  normal 
winter  wind-velocity,  when  room  was  70  deg.  and  zero 
outside,  would  cool  76.3  cu.  ft.  of  air  per  hr.  per  sq.  ft. ; 
see  Table  N.  As  we  find  the  fireplace  loss  to  be  3,975 
cu.  ft.  of-  air  per  hr.  and  the  loss  from  a  square  foot  of 
window  to  be  76.3,  it  follows  that  3,975  -f-  76.3  =  52  + 
sq.  ft.  of  window,  or  about  the  equal  of  two  windows,  3 
ft.  4  in.  X  7  ft.  10  in.,  or  26.11  sq.  ft.  each. 

It  may  seem  to  the  reader  that  with  such  a  multi- 
plicity of  conditions  under  which  heat  is  lost  from  a 

67 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

building  that  it  would  be  a  hopeless  task  to  undertake  to 
supply  and  maintain  any  regular  temperature.  But,  on 
the  other  hand,  the  more  accurately  the  known  sources 
of  loss  are  collected,  the  more  certain  does  the  con- 
tractor become  of  his  ability  to  secure  perfectly  satis- 
factory results.  And  it  might  be  said  also  the  less  in- 
clined is  he  to  rely  upon  "Rules  of  the  Thumb''  when 
figuring  for  radiator  surface  required. 

If  one  should  attempt  to  describe  in  detail  all  the 
various  acts  performed  in  dressing  one's  self  in  the  morn- 
ing to  one  who  had  never  required  clothing*,  it  would 
probably  seem  to  that  one  that  mighty  little  time  would 
be  left  after  the  dressing  was  completed  for  anything 
else. 

It  is  certain  that  no  rules  can  be  given  that  will  obviate 
the  use  of  sound  common  sense  at  times.  It  is  well  to 
remember,  nevertheless,  that  the  more  care  given  in  the 
beginning  to  the  simple  details  which  have  been  described 
as  necessary  while  measurements  are  being  made  and  no 
material  is  being  used  except  pencil  and  paper,  the  more 
certain  will  the  fitter  become  as  to  the  final  net  cost  of 
the  job  when  his  garantee  as  to  temperature  has  been 
filled  and  he  is  ready  for  final  settlement  with  his  client 
for  the  completed  job. 

With  an  acquaintance  among  steam-fitters  extending 
from  the  Atlantic  to  the  Pacific  and  from  the  Great  Lakes 
to  the  Gulf  of  Mexico,  I  can  state  unequivocally  that 
those  men  who  are  really  making  good  money  in  their 
profession  are: 

Those  who  take  the  greatest  amount  of  time  and  care 
to  ascertain  all  probable  sources  of  heat-loss  from  a 
given  job  before  commencing  to  figure  on  it. 

Those  who  exercise  the  greatest  care  in  figuring  the 

68 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

amount  of  surface  needed  in  the  radiators,  to  overcome 
each  loss  when  it  is  apparent. 

It  is  the  men  who  use  one  or  two  short-cut  rules 
to  cover  any  sort  of  house-heating  installation  that 
comes  to  them,  who  are  continually  getting  into  trouble 
over  their  unsatisfactory  jobs. 

These  "short-cut  rule"  men  may  get  their  bids  in 
sooner  than  the  careful  fitter  "who  knows,"  but  the  finish 
of  the  job  and  collection  in  full  from  a  satisfied  client 
will,  9  cases  out  of  12,  come  first  to  the  careful  man 
"who  knows." 

There  are  some  steam-fitters  doing  residence  and  small 
building  wosrk,  in  various  sections  of  the  country,  who 
have  no  knowledge  whatever  of  high-pressure  sky-scraper 
heating  jobs,  but  who  do  know  how  to  figure  a  residence 
properly  for  any  gage  pressure  required  from  10  or  12 
Ib.  less  than  atmosphere  to  30  Ib.  above  atmosphere.  To 
these  men,  for  they  are  few  (may  their  number  in- 
crease), a  set  of  specifications  calling  for  a  half-dozen 
different  temperatures  in  various  separate  rooms  over  a 
house,  coupled  with  a  boiler-gage  pressure  of  specific 
amount,  is  no  staggering  proposition.  It  would  be  to 
the  fitter  who  is  trying  to  cover  everything  with  a  set 
of  guesswork  rules,  or  to  the  fitter  who  only  has  one  rule, 
based  to  be  sure  upon  wall  exposure,  glass  exposure,  and 
change  of  air  in  the  rooms,  but  who  has  not  the  faintest 
idea  whether  the  pressure  called  for  by  the  specifications 
would  agree  with  his  rule  or  not. 

There  are  thousands  of  steam-fitters  in  this  country 
today,  big  concerns  and  little  ones,  who  are  continually 
attempting  to  fit  a  rule  calling  for  10-lb.  pressure  tem- 
perature in  radiator,  to  a  contract  that  calls  for  a  2-lb. 
pressure  at  boiler. 

69 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

These  are  the  people  who  are  having  trouble  with  the 
new  boiler- ratings  and  who  are  sure  radiators  are  much 
overrated  by  the  manufacturers.  These  are  the  people  to 
whom  the  careful  detail  of  measurement  and  the  bringing 
Oi  all  losses  to  the  only  basis  of  measurement  of  heat 
known,  the  B.  t.  u.,  or  its  foreign  brother,  the  calorie, 
are  either  unknown  or  are  considered  by  them  as  beyond 
their  comprehension.  As  can  be  seen  there  is  nothing 
mystic  or  unusual  in  bringing  all  losses  thus  far  found  to 
a  B.  t.  u.  basis.  In  fact,  it  is  the  proper  method,  and  as 
the  discussion  proceeds  it  will  be  seen  that  it  is  the 
logical  thing  to  do  at  every  stage  of  the  proceedings. 

If  the  distance  between  two  points  is  desired;  one  nat- 
urally measures  it  by  feet  or  fraction  thereof,  and  does 
not  attempt  to  do  it  by  getting  a  cubic  foot  of  the  inter- 
vening substance  and  guessing  at  it.  Or,  if  it  is  desired 
to  know  how  much  watef  will  be  required  to  fill  a  cask 
that  is  leaking,  so  that  it  will  just  stay  full,  the  most 
direct  way  is  to  measure  the  quantity  leaked  out  in  a 
given  time,  in  order  to  find  out  how  much  in  quantity 
must  be  replaced  in  a  given  time  It  would  not  be  a 
logical  or  very  successful  way  of  going  about  the  ques- 
tion of  exactly  replacing  the  leakage  from  the  cask  by 
finding  its  cubic  contents  and  guessing  that  from  30  to 
40  quarts  or  gallons  per  hour  would  about  do. 

It  would  be  more  logical  to  measure  the  loss  per 
hour  and,  having  fixed  some  degree  of  velocity  or  pres- 
sure at  which  you  would  pour  the  water  back  into  the 
cask,  say  that  it  would  require  a  certain  quantity  per 
hour  to  offset  the  leakage  out  of  the  cask.  But  if  the 
movement,  the  velocity,  or  pressure  of  the  returning 
water  were  changed  from  the  condition  fixed  by  the  rule, 
either  more  or  less  water  would  be  supplied  than  the 

70 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

balancing  of  leakage  required.  And  that  is  what  hap- 
pens to  the  steam-fitter  who  attempts  to  fit  a  rule  adapted 
to  10-lb.  pressure-temperature  in  the  radiator  to  a  2-lb. 
pressure  at  boiler  condition.  He  does  not  get  heat 
enough.  If  the  reader  has  not  grasped  this  thoroughly, 
refer  to  Section  IV  again. 

Now  that  architects  are  generally  calling  for  results 
with  boiler-pressure  stated  in  advance,  and  final  settle- 
ment is  to  be  made  when  the  temperature  demanded  by 
contract  is  secured  under  conditions  stated,  and  boiler- 
pressure  required  has,  not  been  exceeded,  it  will  not  do  to 
overlook  the  many  little  sources  of  loss,  the  little  leaks. 
If  you  do,  when  settling  time  comes  you  may  be  obliged 
to  spend  many  times  over,  in  adding  sections  to  radiators 
and  in  other  ways,  what  the  cost  to  you  would  have  been 
to  have  taken  time  to  figure  out  these  losses  in  the  begin- 
ning. 

It  is  much  cheaper  to  pay  one  man  for  an  hour  or  two 
of  time  in  properly  figuring  a  job,  than  to  pay  fitters  and 
helpers  for  several  hours'  time  for  extra  work  and  the 
manufacturer  dollars  for  material  that  should  have  been 
provided  in  the  beginning,  if  proper  attention  had  been 
given  to  those  wind-exposed  rooms,  or  that  floor  with  no 
cellar  under  it,  or  the  fireplace  that  was  overlooked,  or 
some  other  bad  loss  of  heat,  of  B.  t.  u. 

It  is  very  certain  that  if  the  total  loss  of  heat  under  all 
conditions  was  the  same,  a  simple  ratio-rule  would  suffice 
to  cover  all  conditions.  It  is  evident  such  conditions  do 
not  apply.  It  is  also  very  certain  that  if  there  was  never 
any  call  for  heating  except  for  10,  15  or  20-lb.  pressure 
of  steam  at  boiler,  that  one  rule  would  answer  for  every- 
thing in  steam-heating.  But  the  fact  is,  architects  and 
owners  call  for  boiler-pressures  varying  from  2-lb.  gage 
at  boiler  to  00-lb. 

71 


A     Practical    Manual    of     Steam    and    Hot-Water    Heating 

Any  rule  that  cannot  be  made  to  supply  the  require- 
ments of  any  condition  of  boiler-pressure,  which  may  be 
called  for  in  residence-heating-,  will  hardly  fill  the  require- 
ments of  the  steam  and  hot-water  fitters  of  today. 

That  a  simple  rule,  easy  to  understand  and  apply,  is  ob- 
tainable, and  is  the  logical  outcome  of  the  natural  laws 
involved  in  heating  by  steam  and  hot-water  when  once 
those  simple  laws  are  understood,  we  are  trying  to  dem- 
onstrate. 

There  are  a  few  more  minor  losses  of  heat  from  a  room 
that  should  not  be  overlooked,  but  often  are  by  careless 
estimators.  A  very  frequent  source  of  trouble  is  second- 
floor  rooms,  whose  floors  also  act  principally  as  the  ceil- 
ing for  an  open  porch.  Very  often  a  half-inch  hardwood 
porch-ceiling  comes  to  be  all  there  is  between  the  cham- 
ber floor-boards  and  "all  outdoors." 

In  these  days  of  hardwood  floors  and  no  carpets,  the 
protection  to  the  room  is  slight  from  such  a  floor,  and 
the  heat-loss  tremendous.  Floors  over  cold  cellars  or 
over  plain  open  space,  must  be  considered.  In  the  South 
and  Middle  West,  quantities  of  fine  houses  have  little 
cellar  room.  They  are  built  on  piers  and  stand  just  high 
enough  above  ground  to  be  dry  and  permit  a  draft 
through  between  floor  and  ground. 

It  is  with  such  conditions  as  these  that  considerable 
judgment  must  be  exercised.  No  hard  and  fast  set  of 
ratio-losses  can  be  fixed. 

The  best  that  can  be  done  is  to  give  an  approximate 
average  as  a  base  upon  which  to  work,  and  such  an  aver- 
age is  shown  in  Table  Q. 

72 


A     Practical    Manual    of     Steam    and    Hot-Water    Heating 

TABLE  Q. 

Approximate  loss  of  heat  in  B.  t.  u.  per  degree  differ- 
ence of  temperature  per  sq.  ft.  of  surface  per  hour  from 
Floors  over  cold-air-spaces: 

With  With 

Double-Boarded  No.         Average         Strong 

Floor.  . .  Draft.  Wind.          Wind. 

\l/2  in.  thick,  open  underneath..       .33  .25  .40 

Floor    double    and    sheathed    on 

underside 22  .25  .29 

Lathed,   and    plastered   with    ce- 
ment on   underside 18  .20  .24 

Two  hundred  and  twenty-four  sq.  ft.  over  an  average 
porch  exposure,  would  lose  from  its  surface  when  room 
was  70  deg.,  outside  air  zero,  from  5,488  B.  t.  u.  to  3,130 
B.  t.  u.  per  hour,  loss  calculated  as  follows :  .35  X  70 
X  224  =  5,488,  or  .20  X  70  X  224  ==  3.136  B.  t.  u.,  ac- 
cording to  conditions. 


SECTION  X. 


It  is  interesting  to  note  in  this  connection  that  a 
good  wall  of  ordinary  quality  will  lose  but  a  trifle 
more  per  square  foot  per  hour  than  that  floor  will 
when  floor  is  in  relatively  same  condition,  having 
lath  and  plaster  on  one  side  of  stud  and  wall  or  floor 
on  other.  See  Table  G  and  Table  I. 

Floors  over  cold  cellars  can  usually  be  considered 
as  having  a  cellar-temperature  of  32  deg.  F.,  and  the 
difference  between  this  and  temperature  of  warm 
room  should  be  taken  in  estimating  loss.  Thus,  the 
cold  air  being  without  wind,  the  loss  is  taken  from 
"No  Draft"  column.  A  double-boarded  floor  with 
no  ceiling  boards  or  lath  and  plaster  counts  by  table 
as  .33  per  deg.  of  difference  per  sq.  ft.  of  surface. 
Then,  70  —  32  =  38;  therefore  38  deg.  X  .33  =  12^  B. 
t.  u.  per  sq.  ft.  per  hr.  A  floor  with  224  sq.  ft.  of 
surface  would  thus  lose  approximately  224  X  12.5  = 
2,800  B.  t.  u.  loss.. 

TABLE  R. 

Showing  approximate  loss  in  B.  t.  u.  per  square  foot 
per  hour  from  warmer  to  colder  rooms  through  ceil- 
ings or  floors.  Room  heated  day  and  night,  not  over 

12  feet  in  height:  T  ,, 

Loss  per  sq.  ft. 

per  deg.  of  Differ. 
Heated  room  having  ordinary  lath  plaster 

ceiling,  board  floor  on  cold  room  above  .60 

This  .60  is  taken  when  using  the  mean  temperature 
of  warm  room  and  of  cold  room  above. 

74 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

As  the  air  in  the  top  of  the  room  is  some  degrees 
warmer  than  average  of  the  room,  and  also  varies 
slightly  according  to  height,  a  loss  averaged  from  sev- 
eral tests  has  been  used.  The  German  authorities  give 
the  loss  through  a  construction  similar  to  our  lath 
and  plaster  ceiling  as  .615.  As  stated  in  the  com- 
mencement, it  is  not  intended  to  fully  cover  the  entire 
heating  proposition  at  this  time,  but  to  cover  quite 
fully,  and  endeavor  to  make  clear  the  fundamental 
laws  of  heating. 

The  first  lesson  to  learn  is  the  use  of  the  measure 
of  heat,  the  thermal  unit.  Unless  a  steam-fitter  has 
learned  this  so  thoroughly  that  he  can  use  it  in  ascer- 
taining losses  or  gains  in  heat,  as  he  would  a  foot-rule 
in  measuring  the  length  of  a  pipe,  he  can  hardly  expect 
any  considerable  accuracy  in  his  heating  undertakings. 

It  is  believed  that  any  one  of  ordinary  attain- 
ments who  has  carefully  read  to  this  point  has  become 
fairly  familiar  with  this  measure  of  heat,  the  British 
thermal  unit. 

We  are  now  ready  to  apply  what  we  have  gathered 
in  regard  to  loss  of  heat  from  rooms : 

Let  us  suppose  that  we  have  a  measurer's  memoran- 
dum of  a  room  on  the  northwest  side  of  a  house  like 
the  following  before  us,  and  proceed  to  apply  to  it 
the  various  things  necessary  to  a  complete  under- 
standing of  how  much  heat,  measured  in  B.  t.  it., 
should  certainly  be  provided  to  offset  the  loss. 

75 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

FORM  AB. 

Measurements  and  figuring  data  from  J.  Plummer 

A.    Bylder,    Architect 

House  of  J.  Robertson 

Street— No.  146 

Telephone   No.— 1953    

R.-F.  D.  No 

Street — Southport    

Town — Springside    

County — Wabash    

State — Indiana     


N\ 


N  W 


UWNCr 


PARLOR 


- 


<rS 


. 

-I*- 


r 

KlTCHEfij      '_ 


P/WING 


76 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 


Name    of    Room 
and 
Temperature   required 

Living  Room.* 
70  deg.  to  zero. 

Compass   location. 
Prevailing  wind. 
Elevation  above  sea. 

N.  E.  14x10.     N.  W.  16x10. 
N.  N.  W.     12  to  15  miles. 
100  to  200   ft.  above  sea. 

Kind  of  wall 
and  condition. 

Brick  good. 

Size  of  room  in 
Feet  and  inches. 

14x16x10  ft. 

Number,  size  and  kind 
of  Windows. 

Four.    6  ft.  6  in.  b  2  ft.  8  in.** 

Number,  size  and  kind 
of    Doors   to   outside 
air  or  Colder  Rooms. 

One.     7  ft.  x  3  ft.  x  2  in. 
Well  fitted. 
Wind  strips  on  sides  and  bottom. 

Temperature,   cold   air. 

Zero. 

Square  feet  exposed 

floor. 

Temperature  of  cold 

side   of   floor. 

Square  feet 
Exposed  ceiling  X 
Roof  or  side  of 
Bay  Window. 
Temperature  of 
cold  side. 


General    Remarks. 


Remarks   on 

Unusual 

Conditions. 


8  x  12  ft. 

To    cold    cellar    32    deg. 
15^-in.  floor. 


Nothing    but 


14  x  16  ft. 

To  cold  room  above  temperature 
32  deg. 


*Has  fire-place  throat  3  x  12  in. 

Chimney  12  in.  x  16  in.  x  30  ft. 

**Well  fitted  except  on  N.  W.  next  fire- 
place and  opposite  door.  This  leaks 
around  finish. 


Cold  cellar  made  to  permit  cold  air  to 
pass  through  it.  Walls  heavy  to  keep 
warmtft  from  main  cellar  coming  in. 
Cold  cellar  32  deg.  Rest  of  cellar  70 
deg. 

Flue  for  heater,  side  of  kitchen  flue.   Size 
12  in.  x  16  in.  x  40  ft.    Clear  and  smooth ; 
no  obstruction  top  or  bottom. 


77 


A    Practical    Manual    of     Steam    and    Hot-Water    Heating 

We  first  find  the  cubic  contents  of  room,  14x16x10 
ft.;  thus  14x16x10  =  2,240  cu.  ft. 

Gross  exposed  wall— 14  +  16x10  =  300  sq.  ft. 
Window  surface — 

6  ft.  6  in.  x  2  ft.  8  in.  x  4  ft.  ==  70  sq.  ft.  70  sq.  ft. 

Oak  door  3  x  7  ft.  ==  21  sq.  ft.  21  sq.  ft. 

Xet  exposed  wall  300—  [70+21]  =1300— 91  209  sq.  ft. 
Net  exposed  floor  8  x  12  ft.  =  96  sq.  ft. 

Xet  exposed  ceiling  14  x  16  ft.  =  224  sq.  ft. 

Fire-place  throat  3  x  12  in.  ==  36  sq.  in.  .25  sq.  ft. 

As  the  memorandum  states  one  window  leaks  around 
finish,  and  is  also  located  opposite  a  door  and  near  fire- 
place, it  is  evident  some  special  judgment  must  be  given 
to  this.  Ordinary  leakage  from  a  first-floor  room  is  con- 
sidered as  twice  the  cubic  contents  per  hour.  This  room 
is  most  unusual  in  its  exposure,  and  this  window  must  in- 
crease the  leakage  in  an  hour  at  least  25  per  cent  of  the 

contents  once,  or 560  cu.  ft. 

Twice  cubic  contents  for  average  leakage.  .  .  .4,480  cu.  ft. 

Total  cubic  feet  of  air-content  to  heat.  .  .  .5,040  cu.  ft. 

As  1.44  B.  t.  u.  will  raise  1  cu.  ft.  of  air  7<>  deg.  (Table 
T)  it  will  require  5,040  x  1.44  =  =  7257  ?>.  t.  u.  to  raise 
contents  and  leakage  to  70  deg.  temperature  required  = 

Contents  and  leakage  loss  =  7,257  B.  t.  u. 

Xet  exposed  wall  [Table  L]  =  209  x  19.12  =  3,996  B.  t.  u. 
Window  loss  [Tables  M  and  X]  70  x  76.3  =  5,341  B.  t.  u. 
Oak  door  [Table  O]  21  x  (.45  x  70)  =  662  B.  t.  u. 

Exposed  floor  [Table  Q]  96  x  (.35  x  38)  1,277  B.  t.  u. 
Exposed  ceiling  [Table  Q]  224  x  23  (70—32  x 

.60  ==  23)  5,152  B.  t.  u. 


78 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

Fire-place  throat   [Table  P]   265  x  60  x 

36/144  =  3,975  B.  t.  u. 


Total  estimated  loss  in  B.  t.  u.  27,660  B.  t.  u. 

No  one  would  for  a  moment  question  that  a  room 
as  above  described  would  be  a  cold  room,  a  very 
difficult  room  to  guess  at. 

The  amount  of  radiation  required  will  depend  en- 
tirely upon  the  temperature  of  hot  water  to  be  used 
or  the  temperature  of  the  steam  used,  which  is  an- 
other way  of  saying  what  pressure.  The  range  of 
size  for  radiator  required  to  heat  this  room  with 
steam  is  from  122  sq.  ft.  with  2-lb.  pressure  at  boiler, 
to  65  sq.  ft.  at  60-lb.  pressure  at  boiler,  or  from  about 
1  to  20  of  cubic  contents  to  1  to  34. 

But  the  amount  that  is  left  to  guess-work  in  this 
case  is  small.  This  room  had  placed  in  it  100  sq.  ft. 
of  2-column  surface  with  guarantee  of  an  average  pres- 
sure at  boiler  of  15  Ib.  per  sq.  in.,  and  numerous  tests 
in  dry  weather  were  perfectly  satisfactory.  See  rule 
for  sizing  direct  radiators.  In  one  test  made  during 
a  heavy  storm  with  wind  estimated  at  30  miles  per 
hour,  and  outside  air  5  deg.  above  zero,  the  room 
temperature  fell  off  slightly  to  65  deg.,  due,  no  doubt, 
to  the  fact  that  no  provision  was  made  for  the  extra 
wind-pressure  beyond  12J/2  miles  per  hour,  nor  for 
the  probably  extra  loss  from  walls  and  fire-place  in 
such  weather.  The  drop  was  not  much  and  was 
easily  provided  for  by  a  trifle  more  pressure  at  boiler. 
This  extra  loss  is  by  tables  found  to  equal  about  2,500 
B.  t.  u.  This,  if  figured  on  at  first,  would  have,  with- 
out doubt,  nearly  or  quite  offset  the  difference,  al- 
though the  moisture  and  excess  wind  might  have 
caused  a  slight  increase  over  table  averages. 

79 


SECTION  XI. 


RADIATOR-SURFACE  REQUIRED  TO  OFFSET 
B.  T.  U.  HEAT-LOSS. 

As  has  been  already  stated,  the  difference  in  tempera- 
ture between  surface  of  radiator  and  temperature  of 
room  determines  the  number  of  heat-units  emitted  from 
radiators. 

When  the  manufacturers  fixed  the  rating  of  house- 
heating  boilers  for  steam  at  2-lb.  pressure  at  boiler,  they 
sounded  the  death-knell  for  nearly  all  the  rules  published 
prior  to  that  time. 

The  heating  contractor  of  today  is  called  upon  to  do 
better  work  than  ever,  and  is  very  largely  called  upon 
now  to  keep  within  the  2-lb.  pressure-limit  called  for  by 
the  boiler  ratings. 

When  discussing  the  specific  and  latent  heat  of  steam 
this  was  explained  to  some  extent.  Table  FF  shows  the 
varying  measure  of  heat  in  B.  t.  u.  which  is  determined 
by  the  different  pressures.  It  is  now  time  to  extend  the 
discussion  to  the  radiating  of  these  heat-units  from  the 
various  forms  of  radiators  styled  Direct,  Indirect,  and 
Direct-Indirect. 

The  direct  radiators  are  most  in  use.  It  is  assumed 
that  it  is  not  necessary  to  go  into  detail  regarding  them 
here,  as  each  manufacturer  of  steam  and  hot  water  ra- 
diators gives  in  his  catalog  full  and  generally  elaborate 
descriptions. 

The  one  thing  none  of  them  give  in  their  catalog  is 
the  value  of  each  style  and  type  of  radiator  in  B.  t.  u. 
per  hour  under  different  temperatures. 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

It  is  not  the  purpose  to  advertise  any  radiator  manu- 
factured here,  but  when  the  time  comes,  as  it  must,  that 
radiators  are  sold  by  their  garanteed  delivery  under 
given  pressure,  of  B.  t.  u.  per  square  foot  per  hour,  the 
price  per  cataloged  square  foot  of  surface  will  materially 
drop  for  some  manufacturers.  A  radiator  rated  in  cat- 
alog at  5  sq.  ft.  per  section,  which  will  deliver  240  B.  t.  u. 
per  hour  when  filled  with  steam  at  212  deg.  and  setting  in 
a  temperature  of  70  deg.,  is  worth  more  money  to  steam- 
fitter  or  owner  than  one  rated  at  5  sq.  ft.,  which  will  only 
deliver  205  B.  t.  u.  per  hour  when  filled  with  steam  at  212 
deg.  in  same  room.  The  former  is  worth  at  least  17  per 
cent  more. 

Today  manufacturers  ask  about  the  same  price  for  each 
representative  pattern.  All  38-in.  two-column  radiators 
are  priced  the  same  and  so  on  through  the  list. 

From  what  has  already  been  said  it  can  be  seen  that  in 
dealing  with  this  question  and  the  present  manner  of 
rating  nothing  but  averages  can  be  given.  Some  manu- 
facturers may  claim  the  average  given  is  low.  It  will 
simply  be  up  to  them  to  garantee  that  their  goods  will 
give  more  than  the  tables  presented  and  then  make  their 
garantee  good. 

There  is  a  difference  between  the  value  of  single- 
column  and  two-column  in  value  per  square  foot,  and 
each  additional  thickness  of  mass  or  column  decreases 
the  value  of  the  direct  radiator  per  square  foot  of  meas- 
ured surface. 

The  B.  t.  u.  emitted  per  square  foot,  as  tabulated  in  this 
series,  is  based  upon  Standard  Three-Column  Radiators, 
as  they  have  been  found  to  average,  unless  otherwise 
stated.  Some  may  do  a  little  better,  and  some  quite  a  bit 

81 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

less  than  the  Table  FF  states  as  the  probable  value  per 
square  foot. 

The  simple  rule  for  final  sizing  of  radiator-surface  for 
a  given  room  is  as  follows,  with  2-lb.  boiler  pressure, 
room  70  deg. 

Rule  for  Sizing  Direct  Radiators,  2-lb.  Pressure  at 
Boiler. 

Divide  the  total  loss  of  heat  from  room  in  B.  t.  u.  by 
220  and  result  will  show  square  feet  of  surface  required. 

Rule   for    Sizing    Direct    Radiators    for   Any    Desired 
Pressure  of  Temperature  at  Boiler  or  in  Radiator. 

Divide  total  loss  of  heat  of  room  in  B.  t.  u.  by  the 
B.  t.  u.  emitted  per  square  foot  of  radiator-surface  at 
the  difference  between  room  and  radiator-temperature. 

The  B.  t.  u.  emitted  from  radiators  can  be  found  by 
multiplying  said  difference  by  2. .5  for  commercial  pipe 
wall-coils;  by  1.S5  for  cast-iron  single-column,  1.05  for 
2-column,  1.0  for  most  3-column,  1.35  for  4-column  cast- 
iron  radiators. 

The  mean  or  average  temperature  of  the  radiators 
should  be  taken  as  95  per  cent  of  the  temperature  of 
steam  at  boiler.  (Tables  F  and  FF.) 

To  apply  this  rule,  having  2-lb.  pressure  at  boiler,  the 
temperature  of  the  steam  is  219  deg.,  95  per  cent  of  that 
or  208  deg.  will  be  the  average  temperature  of  steam  in 
radiators;  if  the  room  is  to  be  70  deg.,  the  difference  is 
138  deg.  A  2 -column  radiator  should  emit  138  X  1-05 
=  228  13.  t.  u.  per  sq.  ft.  per  hour.  A  3-column,  138  X 
1.0  =  220  B.  t.  u.  There  are  types  of  both  two  and 
three-column  radiators  offered  for  sale  that  will  not  give 
as  good  results  as  above ;  there  may  be  others  that  will 

83 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

slightly  exceed.  I  have  tested  3-column  radiators  with 
rather  flat  tubes  that  only  tested  I A  or  193  B.  t.  it.  per 
sq.  ft.  per  hour.  The  fitter  should  require  a  B.  t.  u. 
garantee  from  the  manufacturer  of  any  cast-iron  ra- 
diator, showing  exactly  what  the  heat  emitted  per  sq.  ft. 
per  hour,  at  the  pressure  he  will  require,  is  garanteed 
to  be.  Then  he  will  get  what  he  pays  for. 

SIZING  INDIRECT  RADIATORS. 

It  is  extremely  difficult  to  secure  satisfactory  results 
from  ordinary  indirect  surface  when  confined  to  the  2-lb. 
gage-pressure  at  which  boilers  are  now  rated,  for  the 
reason  that  the  difference  between  the  air  entering  the 
room  from  the  radiator-stack  and  the  room-temperature 
at  70  deg.  is  so  small  that  the  velocity  of  discharge  is 
so  reduced  that  it  is  very  hard  to  get  sufficient  volume 
of  warm  air  into  a  room.  Again  in  using  cast-iron  ex- 
tended-surface radiators,  the  air  is  splendidly  heated  and 
distributed,  it  is  true,  in  its  passage  through  the  radiator, 
but  the  average  temperature  is  thereby  made  lower. 

If  iron  pipe  is  used  the  mass  needed  at  such  low  tem- 
perature as  2  Ib.  at  boiler  deters  one  from  getting  results. 
In  both  cases  the  number  of  heat  units  delivered  for 
room-heating  purposes  per  square  foot  of  radiator  is  less 
than  would  be  delivered  from  same  number  of  square 
feet  of  surface  of  direct  radiators  set  up  in  the  room  to 
be  heated. 

To  attempt  to  heat  a  room  like  that  discussed  for  di- 
rect heating  with  indirect  radiators  and  2-lb.  gage-pres- 
sure at  boiler  would  probably  end  in  some  dissatisfaction 
on  part  of  owner,  unless  he  were  willing  to  go  to  very 
considerable  extra  expense. 

It  is  not  well  to  attempt  to  place  indirect  heating  for 

83 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

any  room  not  provided  with  ventilating  shaft  to  move 
the  air  sufficiently  to  secure  a  comparatively  steady  sup- 
ply of  warm  air  in  motion.  In  fact,  the  attempt  is  likely 
to  invite  possible  dissatisfaction  or  disappointment  with 
indirect  heating. 

But  as  it  is  often  required  by  house-owners  who  believe 
ordinary  leakage  sufficient  for  the  purpose,  the  question 
should  be  discussed  here. 

As  indirect  heating  is  accomplished  usually  by  the  use 
of  extended-surface  cast-iron  indirect  radiators,  it  is  well 
to  remember  that  all  such  radiators  when  cataloged  by 
manufacturers  very  properly  contain  the  entire  surface- 
measurement  of  the  material,  extended  as  well  as  prime 
surface.  Various  manufacturers  adopt  different  designs 
and  arrangement  of  extended  surface  for  their  product, 
so  *that  it  is  desirable  always  to  ascertain,  if  possible 
from  the  manufacturer  the  garanteed  value  of  his  ra- 
diator in  B.  t.  u.  at  the  temperature  you  intend  to  use. 

Failing  to  secure  such  information  it  will,  as  a  rule, 
be  safe  to  figure  the  radiator  for  B.  t.  u.  as  worth  from 
70  to  80  per  cent  of  catalog-value.  There  are,  however, 
so  many  conditions  upon  which  the  net  value  of  indirect 
radiators  depend  that  actual  test  under  conditions  simi- 
lar to  those  to  be  erected  seems  to  be  the  only  safe 
proposition,  unless  the  manufacturer  can  furnish  and 
garantee  the  B.  t.  u.  which  will  be  emitted  each  hour 
under  required  conditions,  per  cataloged  surface  of  his 
material. 

The  tables  given  on  the  value  of  indirects  are  made 
up  from  averages  from  the  results  obtained  from  ordi- 
nary extended-surface  radiators  and  will  be  found  approx- 
imately correct  for  the  better  grade  of  indirects.  The 
contractor  who  is  to  use  indirect  surface  cannot  afford 

84 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

to  use  any  except  the  very  best.  He  may  be  able  to  pass 
through  a  job  of  direct  heating  with  cheap  direct  radi- 
ators, but  with  indirect  heating  he  requires  every  possible 
fraction  of  advantage  to  be  gained  from  the  most  efficient 
goods. 

In  all  jobs  of  indirect  heating  where  only  natural  draft 
is  used,  even  if  a  flue  for  ventilation  is  provided,  there 
will  be  exceedingly  variable  results  obtained,  for  the  con- 
ditions affecting  the  flow  of  air  through  the  radiators 
and  ventilating  shaft  change  many  times  per  day,  and 
occasionally  per  hour.  For  instance,  on  a  squally  day 
the  wind-velocity  may  run  the  range  from  an  almost  per- 
fect 'calm  to  20  or  more  miles  per  hour,  within  a  single 
hour's  time. 

Indirect  radiators  furnish  heat  by  conduction,  there- 
fore without  forced  circulation  the  velocity  of  air  is  low. 
and  heating  value  less  per  square  foot  than  with  forced 
circulation. 

Unfortunately,  the  tables  mostly  in  use  and  the  rela- 
tive proportions  given  as  between  direct  and  indirect 
heating  have,  in  this  country  at  least,  been  based  upon 
tests  made  when  60-lb.  pressure  was  considered  as 
within  the  range  proper  for  house-heating.  These  pres- 
sures are  given  by  Robt.  Briggs  as  late  as  1882  as  being 
the  base  for  the  extensive  tables  he  prepared.  His  tables 
are  based  on  10-lb.  pressure  in. radiator  and  the  use  of 
9.2  cu.  ft.  of  steam  per  minute  per  100  sq.  ft.  of  radiating 
surface  for  direct  heating,  and  from  this  as  a  base  his 
tables  are  carried  to  60-lb.  pressure. 

In  1895,  when  the  Van  Nostrand  edition  of  Robt. 
Briggs'  work  with  additions  by  Alfred  R.  Wolff  was  pub- 
lished, Mr.  Wolff  quotes  Prof.  C.  A.  Smith  and  the  Du- 
buque  Steam  Supply  Co.,  Dubuque,  la.,  and  gives  a  table 

85 


A    Practical    Manual    of     Steam    and    Hot-Water    Heating 

which  he  says  represents  the  results  of  the  practice  of 
these  parties  in  indirect  heating.  This  table  gives  25 
per  cent  as  proper  increase  in  surface  of  indirect  over 
that  which  would  be  figured  for  direct  heating. — Van 
Xostrand  Science  Series,  No.  G8,  pages  117-118-119-121. 

Later  practice  reduced  the  working-pressures  of  direct 
steam-heating  and  a  new  ratio  was  established  between 
direct  and  indirect  surface  by  various  writers  and  50  per 
cent  increase  was  decided  upon  as  about  correct.  In  the 
1900  Edition  of  Prof.  Carpenter's  book  on  "Heating  and 
Ventilation/'  pages  205  and  216,  data  is  given  for  direct 
radiation  at  10-lb.  pressure,  and  for  indirect  radiation  at 
212  deg'.  in  radiator  and  the  ratio  fixed  for  the  first  floor, 
steam  heat,  as  (>f;  2-3  per  cent.  Xow  that  the  practice Jhas 
become  based  on  2-lb.  pressure  at  boiler  for  direct  heating, 
a  new  ratio  becomes  necessary  and  it  will  be  found  desir- 
able to  increase  the  indirect  surface  over  that  required  for 
direct  from  85  per  cent  to  100  per  cent,  according  to  net 
value  of  indirect  surface  used.  The  boiler  manufacturers 
of  the  more  conservative  type  give  notice  in  their  catalogs 
"that  when  indirect  radiation  is  to  be  used  not  less  than 
75  per  cent  increase  over  direct  radiation  should  be 
figured  in  determining  the  size  of  boiler  required."  As 
we  can  see  when  the  matter  is  fully  explained  this  75 
per  cent  increase  is  actually  the  least  that  can  be  used 
with  safety.  A  larger  percentage  of  increase  is  necessary 
on  some  makes  of  boilers.  Personally,  I  would  advise 
an  increase  of  100  per  cent  in  order  to  cover  all  the 
conditions  liable  to  develop,  including  the  fuel  quality 
and  quantity. 

The  conditions  under  which  indirect  radiators  do  their 
work  are  so  completely  different  from  those  of  direct 
heating  that  the  manner  of  determining  the  heating  value 
of  the  surface  is  for  convenience  also  somewhat  changed. 

86 


SECTION  XII. 

To  determine  probable  value  of  indirect  radiator-sur- 
face of  average  cast-iron  extended-surface  radiators  per 
square  foot  of  catalog-surface  per  hour. 

The  indirect  radiator  heats  by  contact  only  and  the 
heat  given  off  is  influenced  by  the  velocity  with  which 
the  air  is  moving  over,  or  coming  into  contact  with  the 
heated  surface  of  the  radiator. 

The  detailed  formula  for  determining  the  B.  t.  u.  is  too 
long  for  insertion  here. 

The  constant  factor  is  found  to  be  0.09825. 

This  is  multiplied  by  the  velocity  at  which  the  air  is 
moving.  It  is  found  that  at  the  low  temperature  of  2-lb. 
pressure  at  boiler  that  a  velocity  of  2  to  4.5  ft.  per  sec. 
is  as  much  as  is  safe  to  figure  on  for  average  indirect 
work.  To  get  indirect-radiator  value,  multiply  0.0982o 
by  3.25,  average  velocity,  to  4.5  and  that  sum  by  435  for 
TO  deg.  in  room  and  deduct  20  per  cent  for  extended 
surface. 

In  order  that  the  manner  of  getting  the  B.  t.  u.  value 
of  indirects  may  be  carried  out  along  the  same  lines  ob- 
served for  directs  (see  page  40  and  Table  FF),  it  may 
be  explained  that  an  indirect  radiator  heats  the  air  by 
contact  only ;  this  air  is  then  conveyed  to  the  room  which 
is  to  be  heated,  the  air  in  the  room  itself  not  coming  into 
direct  contact  with  the  radiator  at  all. 

With  direct-radiator  heating,  the  air  of  the  room  is 
heated  by  direct  contact  and  by  radiation  also,  that  is, 
by  convection  and  radiation. 

Because  of  this  difference  in  method  of  heating  it  is 

87 


A    Practical    Manual    of    Steam    and    Hot- Water    Heating 

evident  that  the  direct  radiator  must  be  the  more  efficient 
per  square  foot. 

We  found  the  value  of  the  direct  3-coltimn  radiator  to 
be  1.6  B.  t.  u.  per  deg.  of  difference  between  the  room 
and  steam  in  the  radiator. 

We  find  by  experiment  that  the  indirect  radiator  must 
be  figured  to  yield  0.805  B.  t.  u.  per  degree  of  difference 
between  temperature  of  steam  in  radiator  at  2-lb.  at 
boiler  and  the  temperature  of  room  at  70  deg.  F.  for  the 
best  grade  of  indirect  with  air  moving  at  an  average  of 
three  and  one-quarter  feet  per  second. 

There  are  indirects  on  the  market  that  can  not  be  fig- 
ured higher  than  0.696  per  degree  of  difference  between 
room  and  steam  temperatures. 

With  2-lb.  pressure  at  boiler,  good  cast-iron  indirects 
can  be  expected  to  yield  111  B.  t.  u.  per  sq.  ft.  per  hour, 
although  some  types  may  not  yield  over  96  B.  t.  u.  per 
sq.  ft.  per  hour  (0.696  X  138  =  96).  As  the  pressure  in- 
creases, the  value  of  the  heating  surface  increases  the 
same  as  with  direct  surface. 

As  the  pressure  increases  the  velocity  may  also  in- 
crease to  some  extent.  But  in  house-heating  it  is  not 
usually  wise  to  allow  for  a  greater  velocity  than  four  and 
one-half  feet  per  second. 

The  B.  t.  u.  emitted  by  average  indirect  radiators  per 
square  foot  per  hour  with  an  average  velocity  of  3.25  ft. 
per  sec.  in  moving  air  is  approximately  as  follows  at  dif- 
ferent pressures. 

TABLE  S. 

Probable  number  B.  t.  u.  emitted  per  sq.  ft.  per  hour 
from  average  cast-iron  indirect  radiators.  Boiler  pressure 
2-lb.  to  15-/&.  Temperature  room,  70  deg. .  Velocity,  2  ft. 

88 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

per  sec.  to  4.5  per  sec.   For  residence  work,  average  3.25 
ft.  per  sec. 


Difference 

Temperature  Be- 

B. t.  u.  Per 

B.  t.  u.  Value 

Lb.  Pressure 

tween  Room 

Deg.  Difference 

Per  Sq.  Ft. 

at  Boiler. 

and  Radiator. 

in  Temperature. 

Per  Hr. 

2  Ib 

138 

805 

Ill 

5  Ib       .. 

.  .    .  .        145 

.814 

118 

10  Ib  

157 

.828 

130 

12  Ib 

162 

834 

135 

15  Ib 

168 

839 

141 

It  is  not  the  intention  to  take  up  ventilation  in  this 
work.  This  is  a  subject  intimately  connected  with  heat- 
ing, to  be  sure,  but  is  also  an  independent  branch  of  the 
work  not  usually  undertaken  by  house-heating  steam-fit- 
ters except  upon  specially  prepared  specifications. 

But  as  occasion  might  arise  where  the  residence-heating 
steam-fitter  might  find  it  desirable  to  figure  out  for  him- 
self other  velocities  than  that  given  in  Table  S  it  is 
thought  well  to  explain  that  table  more  fully.  When  the 
constant  0.09825  is  multiplied  by  the  given  velocity  of 
3.25  ft.  per  sec.  (this  being  the  average)  the  result  is  .319. 
This  multiplied  by  the  number  of  heat  units  emitted  from 
the  radiator  to  the  moving  air,  435  B.  t.  u.  per  hour  at 
the  temperature  of  138  cleg,  difference  between  the  room 
and  the  surface  of  the  radiator,  gives  the  room-heating 
value  of  the  prime  surface  of  the  radiator.  But,  as  20 
per  cent  of  the  average  cast-iron  indirect  radiator  as 
cataloged  is  extended  surface,  it  is  necessary  to  deduct 
that  much  from  the  cataloged  surface  and  to  save  error 
it  is  well  to  do  so  at  this  point.  The  process  is  in  full 
0.09825  X  3.25  =  .319  X  435  =  139  —  20  per  cent  = 
111  B.  t.  u. 

The  same  method  should  be  employed  for  other  veloc- 

89 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

ities  and  pressures.  Table  SS  shows  the  heat  units 
emitted  to  the  incoming  air  per  hour  at  different  temper- 
atures within  the  range  of  present  practice  in  indirect 
house-heating  by  the  radiators. 

TABLE  SS. 

Heat  Units 

Temperature     Difference     Emitted  to  Mov- 
Pressure  of          Between  Room      ing  Air  Per 

at   Boiler.  Radiator.       and  Radiator     Sq.  Ft.  PerHr. 

2  Ib 208  138  435 

5  Ib 215  145  462 

10  Ib 227  157  510 

12  Ib 232  162  530 

15  Ib 238  168  "554 

At  5  ft.  per  sec.  velocity  and  15-lb.  pressure  we  would 
have  0.09825  X  5  =  .491.  This  multiplied  by  the  B.  t.  u. 
emitted  from  the  radiator  to  the  moving  air  at  15-lb.  pres- 
sure =  .491  X  -554  =  272  B.  t.  u.  for  prime  surface.  De- 
duct the  20  per  cent  for  extended  surface  cataloged  and 
you  have  the  value  of  the  radiator  per  square  foot  at  5-ft. 
velocity  per  sec.  in  moving  air  as  238  B.  t.  u.  as  against 
141  B.  t.  u.  when  air  has  3.25  ft.  per  sec.  velocity.  This 
illustration  serves  to  show  very  vividly  how  difficult  it  is 
to  get  satisfactory  results  from  simple  gravity  systems  of 
indirect  heating. 

It  is,  however,  at  times  necessary  to  know  how  much 
heat  in  B.  t.  u.  is  necessary  to  raise  one  cubic  foot  of  air 
to  a  certain  point. 

The  specific  heat  of  air,  0.238,  multiplied  by  the  weight 
of  a  cubic  foot  of  air,  .0864,  will  give  the  amount  re- 
quired to  raise  one  cubic  foot  one  degree.  This  amount 
multiplied  by  the  number  of  degrees  to  be  raised  will 
show  the  total.  Thus  .238  X  -0864  =  .02056  +  this  X 

90 


A     Practical    Manual    of    Steam    and    Hot-Water    Heating 

by  70  —  1.4392  +  B.  t.  u.  required  to  raise  one  cubic  fool 
of  air  from  zero  to  70  deg. 

The  weight  of  air  changes  slightly  as  it  increases  above 
zero.  Therefore,  at  other  minimum  temperatures  than 
zero,  the  decimal  of  weight  per  cubic  foot  changes.  The 
following  Table  T  shows  the  values  of  all  temperatures 
usually  required  in  house-heating  and  domestic  water- 
heating  operations. 


TABLE  T. 

B.  t.  u.  Required  for  Heating  Air. 

.This  table  specifies  the  units  of  heat  required  to  heat  one 
cubic  foot  of  air  at  different  temperatures. 

Temperature  of  Air  in  Room 


t  a 

fig 

w^ 

40° 

50° 

60° 

70° 

80° 

90° 

100° 

110° 

120° 

130° 

-40° 

1.802 

2.027 

2.252 

2.479 

2.703 

2.928 

3.154 

3.379 

3.604 

3.829 

-30° 

1.54011.760 

.980 

2.200 

2.420 

2.640 

2.860 

3.080 

3.300 

3.520 

-20° 

1.290 

1.505 

.720 

1.935 

2,150 

2.365 

2.580 

2.795 

3.010 

3.225 

-10° 

1.051 

1.262 

.473 

1.684 

1.892 

2.102 

2.311 

2.522 

2.732 

2.943 

0° 

0.822 

1.028 

.234 

1.439 

1.645 

1.851 

2.056 

2.262 

2.467 

Z673 

10° 

0.604 

0.805 

.007 

1.208 

1.409 

1.611 

1.812 

2.013 

2.215 

2.416 

20° 
30" 

Q.393 
0.192 

0.590 
0.385 

0.787 
0.578 

0.984  1.181 
0.77010.963 

1.378 
1.155 

1.575 
1.345 

1.771 
1.540 

1.968 
1.733 

2.165 
1.925 

40" 

0.000 

0.188 

0.376 

0.564 

0.752 

0.940 

1.128 

1.316 

1.504 

1.692 

50° 

0.000 

0.000 

0.184 

0.367 

0.551 

0.7350.918 

1.102 

1.286 

1.470 

60° 

0.000 

0.000 

0.000 

0.179 

0.359 

0.538 

0.71810.897 

1.077 

1,256 

70° 

0.000 

0.000 

0.000 

0.000 

0.175 

0.350 

0.525  0.700 

0.875 

1.049 

Above  tables  from  F.  Schumann's  "Manual  of  Heat- 
ing and  Ventilation." 

The  use  of  the  above  table  is  adapted  to  many  pur- 
poses in  heating  problems. 

It  is  often  required  to  know  how  many  B.  t.  u.  will  be 
required  to  raise  a  given  number  of  cubic  feet  of  air 
from  zero  to  70  deg.  or  some  other  temperature. 

91 


A     Practical    Manual    of     Steam    and    Hot-Water    Heating 

Let  us  suppose  it  is  required  to  know  how  many  B.  t. 
u.  would  be  needed  to  raise  2,800  cu.  ft.  of  air  from  20 
below  zero  to  80  deg.  above.  Under  80  deg.  and  oppo- 
site minus  20  deg.  we  note  that  it  will  require  2.150  B.  t. 
u.  to  raise  one  cubic  foot  of  air  from  minus  20  deg.  to 
80  deg.  above,  then,  2800  X  2.150  =  6020  B.  t.  u.  per 
hour.  Or,  if  it  is  desired  to  know  how  many  cubic  feet 
of  air  1303  B.  t  u.  would  heat  from  20  below  to  80  above, 
divide  the  1303  by  2.150 ;  or  from  zero  to  70,  divide  1303 
by  1.439. 

A  great  variety  of  occasions  will  occur  when  this  table 
will  be  found  of  value. 

From  time  to  time  there  is  a  call  for  direct-indirect 
radiators. 

This  type  of  radiator  is  probably  the  least  understood 
as  to  its  requirements  and  limitations  of  any  type  in  ordi- 
nary use. 

While  it  is  not  intended  to  take  up  ventilation,  it  is 
necessary  to  give  a  little  instruction  regarding  direct-in- 
direct radiator  use,  as  this  form  is  the  most  difficult  to 
handle  with  some  degree  of  success  of  all  the  natural- 
draft  systems.  Yet,  when  well  proportioned,  it  is  a  very 
effective  system  within  its  limits. 

The  various  designs  of  the  numerous  manufacturers 
are  so  startlingly  unlike  in  the  amount  of  cold  air  ad- 
mitted per  square  foot  of  rated  surface,  that  until  the 
time  arrives  that  each  manufacturer  states  the  average 
quantity  of  air  which  will  pass,  or  will  give  the  exact 
free  area  for  air  to  pass,  through  his  product  per  section 


92 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

attached  to  cold-air  box,  any  general  rule  for  handling 
direct-indirect  radiators  and  ventilators  will  be  the  rank- 
est kind  of  guess-work. 

Some  have  guessed  25  per  cent  additional,  but  they 
were  using  at  least  15-lb.  gage-pressure  and  some  par- 
ticular make  of  radiator  that  allowed  a  small  amount  of 
air  to  pass  through  it. 

Some  say  50  per  cent  more  than  for  straight  direct 
radiators.  These  again  are  correct  for  certain  particular 
types  of  direct-indirect.  •  With  2-lb.  pressure  at  boiler 
and  the  average  cheap  direct-indirect,  it  is  probable  that 
from  35  to  50  per  cent  more  than  would  be  required  for 
two  or  three-column  direct  radiators  is  not  far  from  cor- 
rect. There  is  at  the  present  time  but  one  direct-indirect 
radiator  on  the  market,  which,  as  cataloged,  is  worthy 
any  serious  attention. 

FIGURING  FOR 
DIRECT-INDIRECT  RADIATION. 

In  figuring  for  direct-indirect,  ascertain  the  cubic  feet 
of  air  the  radiator  you  desire  to  use  will  average  to 
deliver  per  hour  to  room.  Multiply  this  by  1.4  or  1.5 
to  get  number  B.  t.  u.  required  to  heat  the  incoming  air 
to  temperature  of  room,  or  70  deg.  (See  Table  T  oppo- 
site O  and  under  70.)  This  amount  is  what  will  have  to 
be  added  to  the  amount  of  direct  radiating  surface  re- 
quired. 

The  matter  is  simple  as  soon  as  the  number  of  cubic 
feet  of  air  the  radiator  will  permit  to  pass  through  it  per 
hour  can  be  decided. 

The  amount  of  air  which  may  be  expected  to  pass 
through  144  sq.  in.  of  flue  is  given  in  Table  U. 

93 


A     Practical    Manual    of     Steam    and    Hot-Water    Heating 

TABLE  U. 

Cubic  feet  of  air  which  may  be  expected  to  pass 
through  a  flue  144  square  inches  in  area  in  one  hour  with 
a  velocity  of  three  and  one-half  feet  per  second : 

Height 

of  Flue  Excess  of  temperature  in  flue  above  colder  air. 

in  Ft.  20deg.  30  deg.   50  deg.  100  deg.  138deg.  150  deg. 

1  2880  .   3540     4560     6840     7620     7980 

5  6540     8040    10020    14520    17040    17880 

10  9180    11200    14520    20520    24000    25140 


9-1 


SECTION  XIII. 


We  have  now  canvassed  the  question  of  direct 
steam-heating,  indirect  steam-heating,  and  direct-indi- 
rect steam-heating,  and  rules  and  sample  illustrations 
have  been  given  for  practically  every  process  indi- 
cated. 

In  each  case  we  have  found  the  result  depended 
finally  upon  two.  principal  factors. 

First,  the  total  loss  of  heat  from  the  room  expressed 
in  B.  t.  u.,  and  second,  by  the  difference  between  the 
temperature  of  the  steam  in  the  radiators  and  the  air 
surrounding  the  radiator.  This  difference  determined 
the  number  of  B.  t.  u.  each  square  foot  of  radiating 
surface  should  yield. 

We  have  found  that  it  always  requires  the  same 
amount  of  heat  to  raise  a  cubic  foot  of  air  one  degree 
at  the  same  height  above  sea-level.  That  it  requires  70 
times  as  much  to  raise  the  air  70  deg.  That  it  always 
requires  the  same  amount  of  heat  at  sea-level  to  raise 
one  pound  of  water  one  degree  and  that  this  amount  of 
heat  is  the  unit  of  heat-measure,  or  the  B.  t.  u.,  which 
has  been  accepted  as  the  base  upon  which  all  heat 
problems  are  worked  out  with  accuracy. 

We  have  found  that  the  total  loss  of  heat  at  any 
altitude  is  susceptible  to  measurement  by  the  unit  of 
heat,  as  readily  as  distance  is  measured  in  feet,  or 
weight  in  pounds,  or  temperature  in  degrees. 

We  have  found  the  loss  of  heat  through  various  sub- 
stances as  glass,  brick,  wood,  iron,  and  the  like,  varies 

95 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

with  the  substance.  It  varies  also  with  the  velocity 
with  which  the  air  in  contact  with  the  substance  passes 
over  it,  and  this  holds  true  whether  the  moving  air  is 
cnarged  with  a  high  or  low  degree  of  temperature. 

We  have  found  that  if  the  total  amount  of  heat- 
loss  is  ascertained,  that  an  equal  amount  is  required 
to  be  supplied  to  produce  an  equilibrium  and  thereby 
maintain  a  room  at  any  predetermined  point  of  tem- 
perature. 

We  have  seen  that  all  these  things  are  controlled  by 
strict  natural  laws  easily  applied. 

We  have  found  that  steam  at  2-lb.  pressure  at  sea- 
level  is  not  as  hot  when  measured  by  thermometer- 
degrees  as  is  steam  at  30  to  60-lb.  pressure  at  same 
level,  and  that  the  steam  produced  at  a  higher  altitude 
is  not  as  hot  when  measured  by  the  thermometer  as 
at  sea-level. 

From  the  foregoing  summary  of  what  has  been 
investigated  and  explained,  it  is  evident  that  one  or 
two  simple  rules  can  be  made  that  for  ordinary  use 
would  cover  the  required  procedure  for  direct  heating 
by  radiating  surface  placed  in  the  room  to  be  heated, 
providing  some  one  selected  steam-temperature  is  con- 
sidered, and  it  is  also  plain  that  the  only  change  nec- 
essary to  make  the  rule  apply  to  any  gage-pressure 
is  to  change  whatever  number  of  heat-units  is  re- 
quired to  raise  one  cubic*  foot  of  air  from  the  minimum 
to  the  maximum. 

The  fact  that  steam-heating  boilers  for  residences 
and  small  buildings  are  now  rated  as  to  capacity  on 
a  basis  of  2-lb.  gage-pressure  at  the  boiler,  seems 
to  demand  that  any  rule  for  practical  and  general  use 

96 


A     Practical    Manual    of     Steam    and    Hot-Water    Heating 

by  the  trade  should  be  stated  in  terms  that  accord 
with  boiler-ratings. 

The  various  detailed  processes  can  be  summed  up 
then  in  the  following-  rules  for  average  conditions. 
When  special  conditions  of  floor-exposure  or  ceiling  or 
roof-exposure  are  present  the  reader  who  has  followed 
the  discussion  to  this  point  will  know  instantly  the 
course  to  pursue  to  find  out  how  many  additional  units 
are  needed  to  offset  abnormal  conditions. 

General  rules  for  heating  residences  in  zero  weather  to 
70  deg.  with  average  -wind- conditions  when  steam-gage 
pressure  at  boiler  is  at  2-lb. 

Rule  1 — Multiply  the  cubic  contents  of  up-stairs  rooms 
or -twice  the  cubic  contents  of  down-stairs  rooms  by  l.o 
to  find  necessary  heat-units  for  supplying  cubic  contents 
and  leakage. 

Rule  2- — Multiply  the  square  feet  of  net  wall  exposure 
by  19  or  20  to  get  B.  t.  u.  heat-loss  from  walls. 

Rule  3 — Multiply  the  total  square  feet  of  window-sur- 
face by  76.3  to  find  needed  heat-units  to  supply. loss 
from  windows. 

Rule  4 — Multiply  square  feet  of  exposed  floors  by  23  ».o 
find  loss  of  heat  from  this  source.  Multiply  total  square 
feet  of  exposed  ceiling  by  23  if  cold  room  above,  or  by 
42  if  exposed  directly  to  the  outer  air. 

Rule  5 — To  obtain  the  radiating  surface  for  direct 
steam-heating  with  2-lb.  pressure  at  the  boiler,  divide  the 
sum  of  losses  found  by  Rules  1,  2,  3,  4  by  220. 

Rule  6 — To  obtain  the  radiating  surface  for  direct  hot- 
water  heating  with  water  at  boiler  at  180  deg.,  divide  the 
sum  of  losses  found  by  Rules  1,  2,  3,  4  by  160. 

Rule  7 — To  ascertain  square  feet  of  radiation  required 
for  any  temperature  of  hot-water  or  steam,  divide  the 

97 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

sum  of  heat-units  found  by  adding  results  of  Rules  1,  2. 
3,  and  4  by  number  of  heat-units  emitted  per  hour  per 
square  foot  of  radiating  surface  at  temperature  or  pres- 
sure selected  and  the  result  will  be  the  square  feet  of 
radiation  required  at  selected  temperature. 

These  rules  can  be  condensed  when  a  steam-pressure 
of  2-lb.  at  boiler  is  desired,  or  180  deg.  at  boiler,  for  hot- 
water  heating,  into  a  very  simple  form.  Thus : 

Condensed  rule  for  heating  with  direct  radiation  in  zero 
weather  to  70  deg.  2-lb.  steam-pressure  at  boiler,  or  180 
deg.  at  boiler  for  hot  water. 

Divide  sum  total  of  heat-units  required  to  offset  loss 
from  walls,  windows,  exposed  floors,  ceilings  and  leakage 
by  220  for  steam  heat,  or  by  160  for  hot-water  heat. 

The  great  degree  of  exactness  possible  to  obtain  by  the 
processes  detailed  cannot,  it  is  believed,  be  obtained  by 
any  rule  now  in  general  use  among  the  trade. 

As  it  is  often  necessary  to  figure  for  other  steam-pres- 
sures than  2-lb.  at  boiler  or  180  deg.  at  boiler  for  hot- 
water,  a  list  of  divisors  for  use  at  other  pressures  and 
temperatures  is  herewith  given.  These  are  for  use  with 
average  cast-iron  radiator-surfaces. 


TABLE  V. 

Steam-Gage  at  Boiler. 
2-lb                  .  .               

Divisor. 
220 

5-lb     

232 

10-lb  

251 

12-lb  ;.. 

259 

1  5-lb  ,  

284 

20-lb     

297 

25-lb  

324 

30-lb.. 

380 

98 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

Hot  Water  Temp, 
at  Boiler 
Degrees. 

210 206 

200 192 

190 176 

180 160 

170 145 

160 131 

Rule  for  Direct-Indirects. 

To  the  amount  of  direct  radiator  surface  required,  add 
iu  direct-indirects  sufficient  to  offset  the  total  incoming 
air  through  the  indirect  surface.  Usually  about  30  per 
cent  of  2-column  and  from  40  to  50  per  cent  with  3-col- 
umn  radiators. 

Rule  for  Indirect   Heating. 

Divide  the  total  loss  in  heat  units  as  found  by  Rules  1, 
2,  3  and  4  by  111.  For  divisors  for  other  pressures  than 
2-lb.  see  Table  S. 

Generally,  in  hot-water  heating,  where  economy  of  fuel 
and  easy  control  are  desired,  the  divisor  for  170  deg. 
at  boiler  will  be  found  very  desirable.  At  this  tempera- 
ture somewhat  more  radiation  is  required,  it  is  true,  but, 
on  the  other  hand,  in  medium  weather  a  much  lower 
temperature  in  radiators  is  needed  and  the  house  does 
not  become  overheated  in  the  warm  part  of  day  as  is 
quite  liable  to  be  the  case  where  a  high  temperature  in 
the  water  is  needed  to  offset  the  colder  hours  of  the  early 
morning.  It  is  often  found  in  those  sections  where  quite 
warm  hours  occur  during  the  middle  of  the  day  that  if 
water  is  raised  to  a  high  temperature  in  the  morning  that 
it  does  not  cool  down  sufficiently  to  prevent  overheating 
during  those  warm  hours. 

99 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

This  will  be  corrected  by  figuring  the  whole  job  at  a 
lower  temperature.  There  is  also  the  advantage  of 
quicker  response  when  called  upon  for  more  heat. 

Architects  often  desire  to  know  what  temperature  of 
water  or  steam-pressure  a  contractor  proposes  to  compel 
his  client  to  carry.  By  the  aid  of  these  rules  and. divisors 
the  approximate  pressure  or  temperature  is  very  easily 
found. 

A  contractor  who  has  figured  by  these  rules  can  almost 
instantly  tell  what  pressure  or  temperature  a  competitor 
who  proposes  a  different  quantity  of  radiation  must  fur- 
nish to  the  radiators. 

Thus  a  contractor  by  these  rules  has  figured  a  house 
to  be  heated  by  steam  at  2-lb.  at  boiler  and  proposes  440 
sq.  ft.  of  surface.  A  competitor  proposes  to  do  the  job 
using  341  sq.  ft.  and  another  proposes  to  do  the  job  using 
372  sq.  ft.  The  average  owner  at  once  jumps  to  the  con- 
clusion that  the  man  who  wants  to  put  in  440  sq.  ft.  of 
surface  is  wildly  off,  because  the  other  two  are  only  31 
sq.  ft.  apart,  and  they  both  garantee  their  proposal. 

Examining  the  matter,  let  us  assume  that  the  man  who 
offered  440  sq.  ft.  figured  on  2-lb.  at  boiler.  Then  he  fig- 
ured 220  B.  t.  u.  per  hour  per  square  foot.  Therefore 
440  X  220  =  96.800  B.  t.  u.  to  be  furnished  per  hour. 

One  competitor  proposes  372  sq.  ft.,  then  96.800  -f-  372 
will  show  how  many  B.  t.  u.  per  hour  each  square  foot 
must  emit  to  do  the  required  work.  The  division  shows 
260  B.  t.  u.  The  other  man  proposed  341  sq.  ft. ;  division 
in  same  manner  shows  284  B.  t.  u.  A  glance  at  the  table 
given  above  and  it  is  seen  that 

440  sq.  ft.  called  for  220  B.  t.  u.  or  2-lb.  pressure. 
372  sq.  ft.  called  for  260  B.  t.  u.  or  12-lb.  pressure. 
341  sq.  ft.  called  for  284  B.  t.  u.  or  15-lb.  pressure. 

100  " 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

There  is  no  question  that  either  of  the  three  will  heat 
the  house  equally  well,  but  the  amount  of  fuel  and  care 
required  to  produce  results  required  will  be  vastly  dif- 
ferent. 

The  owner  who  "knows"  will  very  quickly  decide  that 
the  man  who  is  widely  off  is  the  man  with  the  one  hun- 
dred feet  less  radiating-surface.  He  will  realize  that 
when  he  begins  to  "kick"  because  of  big  fuel  bills  that  the 
341  sq.  ft.  man  is  the  one  who  is  apt  to  meet  his  protests 
with  the  remark  that  "If  you  expect  to  keep  warm  in 
cold  weather  you  must  expect  to  burn  fuel,"  or  words  to 
that  effect. 

When  it  is  so  easy  to  "know"  it  will  soon  become  out 
of  fashion  to  guess. 

We  have  said  that  with  2-lb.  pressure  at  boiler,  100  per 
cent  should  be  added  for  indirects  to  the  direct  surface 
required.  This  is  very  close  to  what  very  careful  figur- 
ing will  develop,  as  will  be  seen  by  comparing  Table  S 
with  the  table  of  heat  (FF)  emitted  from  direct-radiators. 
Direct-indirect  radiators  require  an  increase  of  from  35 
to  50  per  cent  above  the  amount  required  for  direct. 


101 


SECTION  XIV. 

Piping  to  Steam-Radiators. 

To  those  who  desire  to  carefully  construct  a  steam- 
heating  job,  the  last  thing  in  "laying  out  the  job"  will  be 
the  selection  of  boiler  size,  as  it  is  plain  to  be  seen  that 
the  boiler  must  be  big  enough  to  supply  easily  all  heat- 
losses  from  all  sources,  and  a  very  important  source  is 
piping. 

It  is  common  practice  to  guess  at  the  surface  in  piping. 
Some  will  guess  that  piping  will  equal  10  per  cent  of 
direct  radiator-surface ;  others  20  or  25  per  cent.  It  is 
rare  that  pipe  surface  is  "guessed"  to  be  over  25  per  cent 
of  total  radiating-surface.  Yet  it  often  exceeds  50  per 
cent  on  small  jobs  where  there  are  many  fittings  used, 
elbows,  tees  and  the  like. 

The  discussion  in  regard  to  different  pressures  and 
their  effect  upon  size  of  radiating  surface  has  developed 
the  fact  that  the  higher  the  pressure  carried  the  smaller 
the  radiator  surface  required. 

To  a  marked  degree  this  rule  holds  true  with  piping 
also.  The  usual  piping  formulas  in  use  were  developed 
when  15  to  30,  or  even  60-lb.  pressure  was  in  general  use 
for  house-heating.  As  we  develop  the  facts  in  regard  to 
proper  size  of  pipes  for  steam-heating  this  fact  becomes 
very  distinct  and  important. 

The  first  thing  to  determine  in  regard  to  piping  is  the 
system  to  be  adopted :  Whether  2-pipe  or  single  pipe 
circuit ;  single  pipe  and  relief;  one  pipe  overhead  or  some 
modification. 

102 


A     Practical    Manual    of     Steam    and    Hot-Water    Heating 

Each  of  these  systems  is  good,  and  each  is  especially 
well  adapted  to  some  special  class  of  work.     We  will 


take  them  up  in  order  named.  In  each  system  there  is 
one  thing-  to  be  carefully  safe-guarded  and  that  is  the  so- 
called  water-line  of  boiler. 


103 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 


Unless  this  is  reasonably  steady  under  the  various  pres- 
sures required,  dissatisfaction  develops  at  once. 

As  this  water-line  is  a  constant  source  of  anxiety  to 


Ret  urn  Pi  PC 

& 


fiq.  7. 

many,  if  not  all  fitters,  and  is  present  with  every  system 
mentioned,  it  is  probably  best  to  begin  to  explain  piping 
systems  by  an  explanation  of  why  piping  develops  the 
unsteady  water-line. 

104 


A     Practical    Manual    of     Steam    and    Hot-Water    Heating 

There  is  no  house-heating  boiler  on  the  market  that 
will  not  maintain  a  steady  water-line  under  usual  con- 
ditions of  firing  if  the  openings  provided  for  the  steam  to 
escape  are  attached  to  pipes  discharging  steam  and  con- 
densation to  the  atmosphere,  the  supply  of  water  in 
boiler  being  fed  automatically  as  steam  is  evaporated. 
With  a  connection  of  this  kind  there  would  be  required 
continued  and  excessive  firing  to  develop  a  condition 
where  water  in  the  gage-glass  would  seriously  drop 
below  an  average  point.  This  would  demonstrate  there 
was  nothing  in  the  manufacture  of  the  boiler  that  of 
itself  produced  this  condition  so  often  found  with  house- 
boilers.  If  now,  the  various  openings  from  the  steam- 
chamber  of  boiler  are  connected  up  to  the  return-open- 
ings provided  by  the  manufacturer  at  the  bottom  of  his 
boiler  and  when  the  2,  5  or  10-lb.  pressure  is  developed, 
the  water  in  the  gage-glass  begins  to  fluctuate  or  even 
leave  the  glass  completely,  any  sane  person  would  con- 
clude that  something  about  the  piping  caused  the  effect. 
There  can  be  no  effect  without  first  a, cause;  there  can 
be  no  cause  without  an  effect.  The  first  thing  to  find 
out  then  is  if  any  natural  law  has  been  violated  that  has 
produced  the  unsteady  water-line. 

The  pipes  being  connected  as  per  Fig.  6,  the  line  of 
water-gage  is  steady  as  when  discharging  to  outer  air. 

Connect  as  in  Fig.  7  and  at  5-lb.  pressure  on  gage 
the  water-line  becomes  unsteady  and  with  the  accession 
of  a  little  more  pressure  nearly  or  quite  disappears  from 
sight. 

Connect  as  in  Fig.  8  and  the  water  line  begins  to  trou- 
ble before  gage  shows  pressure. 

Now  for  the  cause.  When  the  pipes  have  been  so  con- 
mcted  that  all  circuits  are  complete,  the  system  is  simply 

105 


A     Practical    Manual    of    Steam    and    Hot-Water    Heating 


like   a   hollow    circular   tube    somewhat   crooked   in   its 
contour. 

If  in  a  tube,  shaped  as  Fig.  9,  water  stands  at  A  and 


Supply  Pipe 


Return  Pipe 

a 


fig.  e>. 


B  it  will  remain  in  each  side  perfectly  even  and  level. 
You  have  a  steady  water-line. 

But  apply  a  small  pressure  at  A  and  the  water  will  no 

106 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

longer  be  at  a  level  with  either  A  or  B.  A  new  line  is 
established  for  A  and  B.  (Fig.  10.)  The  position  of 
the  new  line  will  be  determined  by  the  amount  of  pres- 
sure applied  at  point  A.  Whatever  the  pressure  may  be 
the  water  will  advance  above  B  (Fig.  9),  if  the  tube  is 
high  enough  to  balance  A  plus  weight  or  pressure. 


Water 


Line 


Fiq.  9 


If  the  water  at  B  now  receives  a  pressure  somewhat 
less  than  is  being  exerted  at  A  a  new  position  will  be  as- 
sumed by  the  water  in  both  arms  of  tube.  This  new  po- 
sition will  be  determined  by  the  difference  in  the  pres- 
sure at  A  and  B. 


107 


A    Practical    Manual    of    Steam    and    Hot- Water    Heating 

If,  when  in  piping  a  steam-heating  job,  the  piping  is  so 
placed  that  the  difference  in  pressure  between  the  pres- 
sure on  the  water  in  the  boiler  which  is  represented  in 
Fig.  10  at  A  and  that  on  the  return  water-pipe  of  B 
is  considerable,  the  water  will  leave  the  boiler  water-gage 
glass. 

This  must  now  be  illustrated  by  known  facts.  A  col- 
umn of  water  28  in.  high  exerts  a  square-inch  pressure 
of  approximately  one  pound.  Always  keep  this  in  mind 
when  preparing  to  lay  out  a  steam  job  of  piping. 

It  is  your  purpose  to  carry  a  certain  pound-pressure  at 
the  boiler  on  the  job.  Let  us  say  as  illustrating  the 
idea,  one  pound.  Then  if  you  have  one-pound  pressure 
*bn  the  boiler,  that  is  equivalent  to  28  in.  once,  or  a  column 
of  water  28  in.  high,  it  is  evident  that  if  you  intend  to 
return  the  water  of  condensation  into  the  boiler  that 
somehow  you  must  provide  for  a. greater  pressure  than 
that  in  the  boiler,  or  one  pound. 

This  must  be  done  in  the  pipe  which  drops  from  the 
supply-pipe  end  of  circuit.  Assuming  then  that  the 
piping  was  so  small  that  when  the  circuit  reached  the 
drop-pipe,  there  was  l/4-\b.  pressure  of  steam,  the  water 
would  stand  21-in.  higher  in  the  drop-pipe  than  in  the 
boiler.  In  other  words,  the  two  lines  would  equalize  at 
a  point  21  in.  higher  on  one  side  than  the  water  in  boiler 
because  the  pressure  of  J^-lb.  at  end  of  return  equals  7-in. 
of  water  and  21  +  7  =  28-in.  or  one-pound  pressure.  In 
order  to  get  a  greater  pressure  than  just  an  equilibrium, 
this  standpipe  or  drop  from  circuit  must  be  more  than 
21  in.  above  the  water-line  of  boiler.  This  is  so  that  in 
addition  to  the- pressure  of  >^-lb.  which  equalizes,  there 
may  gather  a  body  or  column  of  water  of  condensa- 
tion of  a  couple  of  ounces  possibly.  This  then  means 

108 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 


four  inches  more  length  at  least  in  that  return  drop,  or  a 
total  of  25  in.  that  the  supply-piping  must  stand  at  its 
lowest  point  above  the  water-line  of  boiler  when  the  drop 
to  below  water-line  of  boiler  is  made. 

The  secret  of  steady  water-line  in  its  last  analysis  is 
found  to  be  absolutely  in  this. 


Water Ltne  A 

Caused  by 

weiqrir  or 

pressure 


HattrLme  d 

to  frafanoe 
nr eight 
pressure  of  A. 


Fiq.  10. 


No  matter  how  many  things  seem  to  cause  unsteady 
water-lines  to  the  extent  of  the  water  leaving  the  boiler 
when  finally  chased  down  to  absolute  cause,  it  will  al- 
ways develop  that  the  prime  effect  of  the  cause,  what- 
ever it  seemed  to  be,  was  to  bring  a  gfeater  pressure  on 
the  water  in  the  boiler  than  was  present  in  the  return- 
pipe  drop  connection  at  boiler. 

109 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

The  secret  of  good  piping  lies  in  the  science  of  so  ad- 
justing the  piping  that  the  point  of  equalization  shall  be 
at  a  point  where  an  ample  excess  of  pressure  can  be  pro- 
vided by  a  steady  upright  column  of  water  in  the  drop- 
line. 

Here  is  where  the  great  difference  among  fitters  as  to 
pipe  sizes  originate.  One  adjusts  his  pipes  so  as  to  re- 
quire great  velocity  of  steam  and  thereby  requiring  a 
very  high  space  between  his  supply-pipe  return-end,  and 
the  water-line  of  boiler. 

Another  requires  a  less  velocity  to  the  steam,  conse- 
quently his  volume  per  minute  is  delivered  with  less  loss 
of  pressure  and  he  can  work  nearer  the  water-line  of  the- 
boiler.     A  third  may  work  on  a  velocity  of  20  or  25  ft. 
per  second  and  his  pressure-loss  is  slight. 

Still  another  may  so  increase  the  size  of  his  pipe  that 
the  loss  of  pressure  is  merely  a  trifle  of  an  ounce.  This 
one  can  work  on  a  distance  above  water-line,  for  his  re- 
turn, of  six  or  less  inches  and  still  have  a  steady  water- 
line.  The  first  one  might  require  five  or  six  feet  drop 
in  order  to  hold  a  steady  line,  but  he  would  use  small  pipe. 

The  craze  for  using  small  pipe  by  men  who  do  not 
know  how  to  calculate  velocity  and  delivery-volume  of 
steam,  has  cost  boiler  manufacturers  many  thousands  of 
dollars  in  trying  to  fix  up  a  job  so  it  would  present  a 
steady  water-line.  This  happened  when  the  only  trouble 
was  with  the  foolish  piping  which  some  contractor  had 
used  on  the  job.  Nine  cases  out  of  ten  if  it  is  suggested 
to  the  fitter  that  the  trouble  is  in  the  piping  he  flies  into 
a  rage  and  begins  to  tell  about  his  great  experience, 
usually  winding  up  by  saying  "he  is  no  theory  man,  he  is 
practical." 

Notwithstanding  all  his  practical  knowledge  and  ex- 

110 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

perience,  which  may  be  very  great,  the  moment  he  pipes 
a  job  so  that  it  will  not  carry  a  steady  water-line  and 
failing  to  fix  it  himself,  calls  upon  the  manufacturer  to 
"fix  his  boiler,"  Mr.  Practical  Man  has  acknowledged  he 
does  not  know  either  the  practice  or  theory  which  pro- 
duces steady  water-lines. 

There  is  a  natural  law  involved  and  no  living  man  can 


BOILER 


I  f 

I      A/0,   1 


T£R     I- I  fit- 


\ 


BOILED 


\ 


NO 


\ 


^H 


'Hf>T'e/?liNe  IN  PIPE 


WATER 
NO    4- 


/VO  6 


A  Condensed  Study  of  the  Water-Line  Question. 

evade  it  or  get  around  it.  A  false  water-line  may  be 
created  in  the  piping  and  a  steady  line  on  boiler-gage  at- 
tained, but  that  simply  proves  that  the  law  can  not  be 
evaded.  It  can  be  fairly  stated  that  if  a  cast-iron  steam- 
boiler  is  so  constructed  that  it  will  carry  a  steady  water- 
line  under  2-lb.  pressure  in  the  factory  or  anywhere  on 
earth  at  one  time,  it  will  continue  to  do  so  for  all  time  so 
far  as  that  type  of  boiler  is  concerned.  If  it  will  carry 


ill 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

a  steady  line  when  the  piping  is  laid  out  properly  in  one 
place,  any  boiler  cast  from  same  patterns  will  continue 
to  carry  a  steady  water-line  so  long-  as  the  piping  is 
properly  adjusted  as  to  size,  velocity  of  steam  and  vol- 
ume to  be  delivered  to  end  of  main,  to  the  distance 
above  the  water-line.  If  this  distance  is  less  than  it 
should  be,  or,  if  it  is  just  enough  for  equalization,  an 
unsteady  water-line  will  result,  and  that  whether  the 
man,  who  laid  it  out  and  put  it  in,  is  the  best  engineer 
on  earth  or  the  poorest. 

Tt  is,  therefore,  evident  that  in  order  to  lay  out  the 
piping  for  a  steam  job  it  is  still  necessary  to  "know" 
instead  of  guess,  fully  as  much  so  as  in  figuring  ra- 
diation. But  unfortunately  for  all  concerned,  the  wild- 
est guessing  contest  in  the  whole  heating  business  is 
the  sizing  of  pipes  by  the  steam-fitting  men,  who 
blindly  follow  a  book-rule  they  have  picked  up  some- 
where. They  have  not  the  faintest  idea  as  to  what 
velocity  the  steam  will  have  to  assume  to  supply  the 
demand  they  have  made  on  it,  nor  where  the  return 
must  drop  below  the  water-level  of  the  boiler  in  order 
that  the  water-line  may  remain  satisfactorily  steady. 


112 


SECTION  XV. 


The  problem  is  not  a  difficult  one  to  solve  for  the 
man  who  is  willing-  to  use  his  thinking  outfit  for  a 
short  while.  It  is  a  question  that  really  should  be 
presented  in  algebraic  form,  but,  as  in  the  beginning, 
I  promised  to  explain  these  things  clearly  without  al- 
gebra, I  will  attempt  to  explain  this  piping  question  so 
clearly  that  any  intelligent  workman  can  understand 
and  apply  the  theory. 

Don't  get  nervous  over  that  word  theory.  No  man 
ever  accomplished  anything  out  of  the  regular  line  of 
endeavor  unless  in  some  way  some  theory,  conscious 
or  unconscious,  anticipated  the  accomplishment.  The 
theory  may  have  been  wrong,  but  the  mind-action  pre- 
ceded the  accomplishment,  right  or  wrong.  After  a 
successful  accomplishment  of  an  idea,  the  whole  work- 
ing-out process  will  be  tabulated  into  a  series  of  facts, 
and  this  series  of  facts  will  become  the  theory  upon 
which  all  can  proceed  with  certainty  that  the  theory 
practically  applied  will  produce  satisfactory  results. 
A  man  not  knowing  the  theory  upon  which  the  work 
should  progress  may  at  some  point  deviate  from  the 
true  theory  and  produce  very  unsatisfactory  results. 

Piping  for  steam  is  really  the  development  of  one  of 
Nature's  laws.  From  what  has  been  said  it  is  evident 
that  if  pressure  in  the  pipes  becomes  much  reduced  by 
the  time  the  steam  has  completed  its  circuit  that  the 
pressure  must  be  restored  and  some  added  to  it  before 
the  water  of  condensation  can  enter  the  boiler.  Our 

113 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

first  inquiry  then  is  tD  see  what  causes  loss  of  pressure 
and  if  more  than  one  thing  contributes  to  the  loss. 

The  steam,  in  its  passage  through  the  pipes  and  ra- 
diators is  constantly  giving  up  to  the  surrounding  air 
the  latent  heat-units  it  contains.  As  these  heat-units 
depart,  something  of  measure  and  strength  goes  out  of 
the  steam.  Its  bulk  decreases  and  its  heat  decreases, 
and  therefore  in  corresponding  measure  its  pressure. 
As  this  continues  the  time  comes  when  the  expansive 
force,  or  pressure,  has  all  been  absorbed  and  nothing 
remains  but  water  without  pressure.  Another  item  is 
friction,  every  atom  of  pressure  or  strength  exercised 
in  overcoming  friction  leaves  just  so  much  less 
strength  or  pressure  in  the  steam  to  continue  along 
the  journey.  The  size  of  the  pipe  then  must  exercise 
a  powerful  influence  for  friction,  elbows,  tees,  coup- 
lings, bends,  valves — all  these  fittings  take  strength 
out  of  the  steam  in  its  effort  to  get  by  these  resisting 
items.  They  all  help  reduce  the  strength  with  which 
the  steam  started  out  from  the  boiler.  Nature  has  in 
this  respect  no  different  law  for  steam  when  it  is  doing 
work  than  it  has  for  you.  If  you  start  out  strong  and 
vigorous  to  get  to  a  certain  point  by  a  certain  time,  to 
accomplish  a  certain  task  of  work,  but  on  your  way 
have,  instead  of  smooth,  level  roads,  ravines  and 
swamps  to  fight  your  way  through,  huge  boulders  to 
climb  over,  long  detours  instead  of  straight  lines  of 
road,  you  find  yourself  exhausted  with  exertion  long 
before  your  proposed  destination  is  reached.  You  have 
no  strength  left  for  performing  your  proposed  task 
or  work. 

Nature  has  decreed  that  if  steam  has  quantities  of 
fittings  to  overcome,  in  its  journey,  and  undue  friction 

114 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

to  remove,  in  addition  to  giving  out  its  heat  to  rooms, 
that  its  strength  or  pressure,  as  we  term  it,  in  steam, 
shall  rapidly  decrease. 

Now  this  decrease  in  pressure  can  be  measured  with 
considerable  accuracy  in  advance.  When  a  compact 
little  house-job  has  a  great  many  fittings  within  close 
distance  of  each  other,  a  pipe-size  that  might  be  per- 
fectly proper  on  another  job  with  same  amount  of  ra- 
diation, may  be  not  at  all  the  proper  size  for  that  job. 
The  velocity  of  the  steam  in  the  pipes  increases  the 
friction  and  consequently  reduces  pressure.  Professor 
Carpenter,  of  Cornell  University,  in  his  book  on  "Heat- 
ing and  Ventilating  Buildings,"  states  that,  "the  fric- 
tion in  a  pipe  when  steam  is  moving  at  a  velocity  of 
100  ft.  per  sec.  causes  a  reduction  in  pressure  of  l*/2~ 
Ib.  in  100  ft. ;  a  velocity  of  50  ft.  a  sec.  causes  about 
%  as  much,  and  a  velocity  of  25  ft.  about  1-16  as  much." 

According  to  this  data,  steam  moving  at  a  velocity 
of  100  ft.  per  sec.,  with  an  initial  pressure  of  2  Ib.  or 
the  equivalent  of  56  in.  of  water  head,  will  at  the  end 
of  the  flow  through  100  ft.  of  straight  pipe  only  have 
a  pressure  of  the  equivalent  of  a  14-in.  head  of  water. 
It  will  be  seen  that  with  56-in.  as  initial-head  and  a 
14-in.  head  at  the  end  of  run  that  the  equalization 
point  would  be  42  in.  above  the  water-line  of  boiler. 
To  this  42  in.  must  be  added  about  4  in.  more  to  hold 
the  water  of  condensation  in  order  to  create  in  that 
drop-pipe  the  necessary  extra  pressure  on  the  return- 
pipe  to  put  water  into  the  boiler.  (See  Section  XIV. 
Piping  to  Steam  Radiators.) 

Reduce  the  velocity  by  increasing  the  size  of  the 
pipe  so  that  a  large  volume  of  steam  can  move  on  its 
way  doing  all  the  work  the  first  did  as  to  heating, 

115 


A     Practical    Manual    of    Steam    and    Hot-Water    Heating 

but  not  so  much  strength  spent  in  overcoming  fric- 
tion, using  the  same  initial  head  of  2  Ib.  or  56  in.  of 
water,  and  at  the  end  of  the  100  ft.  the  slower  moving, 
but  larger  volume  of  force  arrives  with  a  strength, 
or  pressure  left,  equal  to  a  head  of  water  of  45%  in. 
or  a  difference  of  10^2  in.  between  head  and  heel. 
With  this  velocity  then,  a  difference  of  14!/2  °r  15  in. 
between  water-line  of  boiler  and  return-end  of  supply 
would  answer  perfectly. 

Increase  the  size  again  so  that  the  velocity  shall  be 
35  ft.  or  less  per  sec.  with  same  head  of  56  in.  of  wa- 
ter and  the  other  end  of  the  100  ft.  of  straight  pipe  is 
reached  with  nearly  all  the  pressure  or  strength  with 
which  it  started.  The  loss  is  only  about  2^2-in.  of 
head.  The  point  of  equalization  is  now  so  close  that 
a  distance  of  five  or  six  inches  would  produce  a  steady 
water-line. 

The  question  is  very  frequently  asked  whv  it  is 
engineers  differ  so  widely  as  to  pipe-sizes.  I  think  the 
question  fully  answered  in  the  above  discussion,  but 
T  will  here  give  a  definite  illustration. 

Mr.  A  makes  a  lav-out  for  a  small  job  of  steam- 
heating-  with  total  radiation  of  200  sq.  ft.  He  figures 
that  the  job  should  be  a  2-pipe  job  with  a  2-in.  supply 
pipe  and  a  24-in.  return. 

Mr.  B  figures  the  same  job  and  calls  for  a  1^4 -in. 
supply  and  a  ^-in  return. 

Mr.  C  figures  for  a  1-in.  supply  and  a  ^-in.  return. 

All  of  them  require  a  boiler  pressure  of  10  Ib. 

Which  of  the  three  is  in  error? 

Supposing  each  to  be  a  competent  engineer  all  the 
way  through,  neither  of  them  can  be  said  to  be  in 
actual  error. 

116 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

Mr.  A  is  figuring  on  exceedingly  slow  velocity  in 
order  to  get  his  main  down  close  to  water-line  of 
boiler  and  still  hold  a  steady  water-line. 

Mr.  B  is  figuring  on  a  much  higher  velocity  to  the 
steam  and  expects  to  drop  below  the  water-line  of  the 
boiler  when  18  or  20  in.  above  it. 

Mr.  C  is  figuring  on  a  very  high  velocity  to  the 
steam  and  expects  to  drop  below  the  water-line  of  the 
boiler  when  the  return  end  of  his  main  is  at  least  46 
to  48  in.  above  the  water-line  of  the  boiler. 


117 


SECTION  XVI. 


All  of  these  jobs  would  work  nicely  and  probably 
give  satisfaction,  but  the  man  who  knew  the  most  or 
paid  the  most  attention  to  detail  of  his  office  work  had 
the  low  bid.  The  total  weight  of  steam  delivered  to 
the  radiators  would  not  materially  differ  in  either 
case,  but  the  amount  of  extra  steam  required  for  over- 
coming friction  would,  in  a  large  job,  show  in  the  fuel 
account. 

From  the  foregoing  it  will,  I  think,  be  perfectly  clear 
how  different  engineers  may  differ  very  materially  in 
pipe  sizes  for  a  given  job.  They  are  simply  working 
out  different  theories  and  different  pressures. 

There  is  one  thing  not  to  be  overlooked.  These  very 
small  pipes  calling  for  high  velocities  are  not  pro- 
ductive of  much  value  to  the  house-owner  in  mild 
weather  from  the  vapor  of  steam.  It  has  vitality  or 
strength  enough  to  work  its  way  very  slowly  through 
the  larger  pipes,  but  the  small  pipe  is  very  difficult 
for  it. 

Now  that  house-heating  boilers  are  rated  at  2-lb. 
pressure  at  boiler,  it  should  be  explained  how  to  figure 
out  the  sizes  that  should  answer  for  certain  velocities. 
In  attempting  to  explain  this  without  algebra.  I  shall 
limit  the  explanation  to  jobs  based  on  2-lb.  pressure 
at  boiler  and  the  use  of  average  quality  of  cast-iron 
radiators  rated  for  4  or  5  sq.  ft.  per  section. 

We  have  seen  that  the  average  radiator  above  de- 
scribed at  a  pressure  of  2-lb.  at  boiler  gives  out  on  an 

us 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

average  220  B.  t.  u.  per  sq.  ft.  per  hr.  when  it  is  zero 
outside  and  the  room  is  at  70  deg.  (Table  FF).  It  has 
been  shown  that  the  total  B.  t.  u.  which  a  job  must 
be  supplied  with,  through  the  pipes,  will  equal  the 
total  square  feet  of  radiation  multiplied  by  220  B.  t.  u. 
given  off  by  one  square  foot  equal  total  B.  t.  u. 

To  supply  this  total  amount  of  heat  in  B.  t.  u.  a  cer- 
tain number  of  pounds  of  steam  must  be  supplied  each 
hour.  To  deliver  this  required  number  of  pounds  of 
steam  through  a  pipe  of  one  size  will  certainly  require 
a  certain  velocity  per  second;  through  a  larger  pipe, 
another  velocity,  and  so  on.  Therefore,  the  velocity 
of  the  steam  must  depend  upon  the  area  of  the  pipe  to 
quite  an  extent. 

.  In  making  comparisons  with  various  tables  of  the 
properties  of  steam  as  given  by  different  writers  it  will 
soon  be  noticed  that  there  is  some  considerable  differ- 
ence, especially  in  the  figures  for  weight  and  volume; 
this  is  caused  by  the  fact  that  that  portion  of  the  table 
is  derived  from  experiment  with  some  and  from  form- 
ulae in  other  cases. 

The  tables  most  in  use  in  this  country  are  those  of 
Porter,  Clarke,  Buel,  Derry  and  Peabody.  There  is 
no  considerable  difference  between  these  authorities 
in  the  important  items  of  temperature,  total  heat, 
latent  heat,  as  given  in  their  various  tabulations. 
Therefore,  so  far  as  house-heating  estimates  are  con- 
cerned, almost  any  table  of  steam  properties  can  be 
used  with  safety.  In  the  following  table  the  gage- 
pressure  is  followed  by  the  absolute  pressure  so  that 
the  difference  can  be  seen  at  a  glance.  This  is  because 
in  some  sections  of  the  country  architects  generally 
call  for  absolute  pressure  instead  of  gage-pressure. 

119 


A    Practical 

Manual    of 

Steam    and    Hot-  Water 

Heating 

TABLE  W 

Table  of  the  properties 

of  steam  from 

Total  Heat 

Vacuum 

Absolute 

Above  32 

Inches  of 

Pressure  Ib. 

i"rknirif*t*n  turf1 

Mercury. 

Per  Sq.  In. 

Fahrenheit.                in 

Water. 

29.74 

.089 

32 

0 

29.19 

.359 

70 

38 

28.90 

.502 

80 

48 

28.00 

.943 

100 

68 

27.88 

1. 

102 

70 

25.85 

2. 

126 

94 

23.83 

3. 

141.6 

110 

21.78 

4. 

153 

122 

17.70 

6. 

170 

139 

13.63 

8. 

183 

152  . 

9.56 

10. 

193 

162 

5.49 

12. 

202 

171 

1.41 

14. 

210 

179 

Atmospheric 

^ 

Pressure. 

14.7 

212 

180.9 

Gage- 

Pressure 

in  Lb. 

1     " 

15.7 

215 

184 

2    " 

16.7 

219 

188 

3     " 

17.7 

222 

191 

4     " 

18.7 

224 

193 

5     " 

19.7 

227 

196 

6     " 

20.7 

230 

199 

8     " 

22.7 

235 

204 

10     " 

24.7 

239 

208.5 

12     " 

26.7 

244 

213 

15     " 

29.7 

249.6 

219 

20     " 

34.7 

258.7 

228 

25     " 

39.7 

266.7 

236.5 

30     " 

44.7 

273.9 

243.9 

120 


A    Practical    Manual    of    Steam 

and    Hot-Water    Heating 

29.7  in.  of  vacuum  to 

TABLE  W. 

30  Ib.  gage-pressure. 

Total  Heat 

Above  32 

Latent  Heat 
In  Heat  Units, 
Steam. 

Volume 
1-Lb.  Steam. 
Cu.  Ft.  in 

Weight 
Ft.  Steam, 
of  1  Cu. 

in  Steam 

1091.7 

1091.7 

3333.3 

.00030 

1103.3 

1065.3 

875.61 

.00115 

1106.3 

1058.3 

635.80 

.00158 

1112.4 

1044.4 

349.7 

.00286 

1113.1 

1043.0 

334.23 

.00299 

1120.5 

1026.0 

173.23 

.00577 

1125 

1015.3 

118 

.00848 

1129 

1007 

90 

.01112 

1134 

995 

61 

.01631 

1138 

986 

47 

.02140 

1141 

979 

38 

.02641 

1144 

973 

32 

.03136 

1146 

967 

28 

.03625 

1146.6 

965.7 

26.36 

.03794 

I 

1148 

963 

24 

.04110 

1149 

961 

23 

.04325 

1150 

958 

22 

.04592 

1150.5 

956 

21 

.04831 

1151 

955 

20 

.05070 

1152 

953 

19 

.05237 

1153 

949 

17.5 

.05711 

1155 

946 

17 

.06183 

1156 

043 

15 

.06651 

1158 

939.2 

13.61 

.07350 

1160.8 

932.5 

11.76 

.08507 

1163.3 

926.8 

10.35 

.09653 

1165.5 

921.6 

9.27 

.1079 

121 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

In  this,  as  in  most  heating  problems,  the  question 
must  be  brought  to  some  definite  standard  from  which 
to  work.  In  this  pipe  question  the  standard  is  100  ft. 
in  length  of  straight  pipe. 

In  order  to  get  this  before  us  clearly,  suppose  we 
find  out  how  small  a  pipe  can  be  used  to  supply  760  sq. 
ft.  of  3-col.  cast-iron  radiation  with  steam  at  25  ft. 
velocity  per  sec.,  2-lb.  pressure  at  boiler.  At  this  pres- 
sure each  square  foot  of  radiating  surface  will  emit  220 
B.  t.  u.  per  hr.,  760  X  220  =  167,200  B.  t.  u.  per  hr.  From 
Table  W  on  "Properties  of  Steam"  we  note  one  pound 
of  steam  gives  up  966  B.  t.  u.  in  process  of  condensa- 
tion. (Actual  965.7.  Commonly  called  966.) 

We  must  furnish  167,200  B.  t.  u.  per  hr.  One-pound 
steam  furnishes  966;  then  167,200-^966  shows  that 
we  must  deliver  173  Ib.  steam  per  hr.  From  the  same 
table  we  learn  that  one  pound  of  steam  at  that  tem- 
perature makes  26.4  cu.  ft.  Therefore  173  Ib.,  multi- 
plied by  26.4  =  4,567  cu.  ft.  per  hr.  to  be  delivered. 
There  are  3,600  sec.  per.  hr. ;  then  4,567  -f-  3,600  =  1.27 
cu.  ft.  per  sec.  We  desire  a  velocity  of  25  ft.  per  sec., 
therefore  we  divide  1.27  by  25  to  find  the  area  in  square 
feet.  Thus  1.27  -f-  25  =  0.05  of  a  square  foot  needed 
in  the  pipe,  144  sq.  in.  X  0.05  —  7.2  sq.  in.  in  area. 
The  Table  of  "Area  of  Circles,"  Table  A,  shows  that 
a  3-in.  pipe  with  an  area  of  7.068  could  be  used,  al- 
though if  it  was  a  question  of  close  fit  for  steady  wa- 
ter-line, a  3 ^2 -in.  pipe  would  be  required. 

Supposing  50  ft.  velocity  to  be  required.  Then  1.27 
-f-  50  =  0.0254  sq.  ft.  144  sq.  in.  X  0.0254  =  3.66  sq. 
in.,  a  2^-in.  pipe  being  the  nearest  commercial  size, 
Supposing  110  ft.  per  sec.  to  be  required.  Then  1.27 

122 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

-7-110  =  0.0115  sq.  ft.  144  sq.  in.  X  .0115  =  1.66  or  a 
ll/2-in.  pipe. 

All  of  this  is  for  2-pipe  direct-heating.  If  single 
pipe  work  is  to  be  used  an  area  equal  to  supply  and 
return  of  2-pipe  work  must  be  used. 

To  illustrate  this,,  the  25-ft.  velocity  called  for  7.2 
sq.  in.  Multiply  this  by  1.5  (or  area  of  supply  and 
return  pipes  in  2-pipe  work).  Then,  7.2  X  1.5  =  10.8. 
The  nearest  commercial  size  is  a  4-in.  pipe,  which 
would  be  required  for  single-pipe  work  at  25-ft.  ve- 
locity. At  50-ft.  velocity,  a  3-in.  pipe  would  be  needed 
and  at  110-ft.  velocity  a  2-in.  pipe. 

These  high  velocities  should  not  be  attempted  on 
house-heating.  With  2  to  5-lb.  pressure  a  velocity  of 
from  25  to  50  ft.  per  sec.  is  as  high  as  should  be  at- 
tempted. 

If  indirect  is  to  be  used,  double  the  area  in  square 
inches  of  2-pipe  direct  requirements. 

Many  fitters  who  have  not  had  the  opportunity  to 
study  into  this  question  of  relation  to  water-line  of 
boiler  and  velocity,  often  erect  jobs  with  pipe  so  ar- 
ranged that  a  drop  of  at  least  30  to  40  in.  is  required 
to  equalize,  and  yet  they  will  not  have,  sometimes, 
half  of  that. 

Of  course,  the  water  "goes  out"  of  gage-glass  be- 
fore a  pound  of  steam  is  registered  and  a  great  howl 
goes  up  about  the  boiler.  Yet  the  trouble  was  not  in 
the  boiler.  This  book  is  being  written  that  those  who 
will  may  take  a  few  moments  to  multiply,  add,  sub- 
tract, and  divide  figures  and  figure  out  for  themselves 
where  the  trouble  is,  or  else  do  better,  and  figure  out 
in  advance  what  piping  will  be  right  in  a  given  case, 

123 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

thus  saving  themselves  many  hours  of  hard  work  and 
perhaps  many  troublesome  hours  with  an  irate  owner. 

It  is  exceedingly  doubtful  if  any  boiler-manufac- 
turer ever  sent  out  a  steam-boiler  which  would  not 
maintain  a  steady  water-line  if  the  piping  had  been 
properly  adjusted  to  the  conditions  in  which  it  was  set. 

Friction  in  fittings  causing  decrease  in  pressure 
seems  to  be  very  generally  overlooked  by  the  average 
steam-fitter.  He  probably  has  about  his  office  a  "List 
of  Pipe-Sizes  for  Steam  and  Hot-Water  Heating,"  and 
this  is  rather  blindly  followed  under  any  and  all  con- 
ditions. Fortunately,  these  lists  of  sizes  are  for  the 
most  part  comparatively  safe  for  housework,  but  often 
fail  on  very  compact  jobs  with  many  radiators  and  on 
the  other  extreme  of  very  long  runs  of  pipe  with  many 
elbows. 


124 


SECTION  XVII. 


It  must  be  remembered,  or,  at  least  always  should  be 
remembered,  that  those  "Lists  of  Pipe-Sizes"  nearly 
all  have  a  note  attached,  or  a  statement  is  made,  that 
for  over  100  ft.  in  length  the  size  is  to  be  increased  a 
certain  amount. 

TABLE  X. 

Table  for  the  Capacity  of  Steam-Pipes  100  Ft.  in 
Length  with  Separate  Returns. 

By  A.  R.  Wolff. 


—  2-lb.  Pressure  — 

—  5-lb.  Pressure  — 

Diam. 

Diam. 

Total  Heat  Radiating 

Total  Heat  Radiating 

Supply 

Return 

Transmitted 

Surface 

Transmitted 

Surface 

in  Ins. 

Ins. 

B.  T.  U. 

Sq.  Ft. 

B.  T.  U. 

Sq.  Ft. 

1 

1 

9,000 

36 

15,000 

60 

IK 

1 

18,000 

72 

30,000 

120 

1/2 

IK 

30,000 

120 

50,000 

200 

2 

1/2 

70,000 

280 

120,000 

480 

2^ 

2 

132,000 

528 

220,000 

880 

3 

2^ 

225,000 

900 

375,000 

1,500 

3J4 

2H 

330,000 

1,320 

550,000 

2,200 

4 

3 

480,000 

1,920 

800,000 

3,200 

4/2 

3 

690,000 

2,760 

1,150,000 

4,600 

5 

3H 

930,000 

3,720 

1,550,000 

6,200 

6 

3^ 

1,500,000 

6,000 

2,500,000 

10,000 

7 

4 

2,250,000 

9,000 

3,750,000 

15,000 

8 

4 

3,200,000 

12,800 

5,400,000 

21,600 

9 

4H 

4,450,000 

17,800 

7,500,000 

30,000 

10 

5 

5,800,000 

23,200 

9,750,000 

39,000 

12 

6 

9,250,000 

37,000 

15,500,000 

62,000 

14 

7 

13,500,000 

54,000 

23,000,000 

92,000 

16 

8 

19,000,000 

76,000 

32,500,000 

130,000 

125 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

Table  X,  the  most  accurate  of  these  lists,  is  that  of 
Prof.  R.  C.  Carpenter  and  A.  R.  Wolff,  but  they  insert 
the  following  notes :  Note  No.  1 — "This  table  is  com- 
puted for  straight  pipes  with  water  level  in  return  6  in. 
above  that  in  boiler.  In  case  there  are  bends  or  obstruc- 
tions consider  the  length  of  pipe  increased  as  follows : 
Right  angle  elbow,  40  diameters ;  globe-valve,  125  diam- 
eters; entrance  to  tee,  60  diameters."  The  italics 
are  put  in  by  the  writer  of  this  book.  This  note  No.  1  is 
under  Professor  Carpenter's  single-pipe  steam  table,  in 
which  a  3-in.  main  is  given  for  1,000  sq.  ft.  of  steam  at 
10-lb.  initial  pressure. 

Note  No.  2  is  under  A.  R.  Wolff's  table  for  2-pipe 
steam  and  reads  as  follows  :  "For  pipes  of  greater  length 
than  100  ft.,  multiply  results  in  above  table  by  the  square 
root  of  100  divided  by  the  length."  In  all  cases  the  length 
is  to  be  taken  as  the  equivalent  length  in  straight  pipe  of 
the  pipe,  elbows  and  valves  as  previously  given." 

"In  above  table  each  square  foot  of  radiating  surface 
is  assumed  to  transmit  250  heat-units  per  hour." 

"For  other  lengths  multiply  above  results  by  following 
factors  :  Length  of  pipe 

in.  ft 200  300  400  500  600  700  800  900  1,000 

Factor  0.71  0.58  0.5  0.45  0.41  0.38  0.35  0.33  0.32 

"For  example,  the  capacity  of  a  pipe  8  in.  in  diam- 
eter and  800  ft.  long  would  be  0.35  of  12,800  sq.  ft.  of 
radiating  surface  =  4,480  sq.  ft." 

From  above  it  will  be  noted  that  supposing  an  8-in. 
main  155  ft.  long  had  on  it  6  ells,  8  tees,  2  globe- 
valves,  its  length  should  be  considered  as  800  ft.  of 
straight  pipe  and  only  4,480  sq.  ft.  2-pipe  radiation  at 
2-lb.  pressure  attached. 

How  many  fitters  follow  this  advice? 

126 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

Mr.  Wolff  gives  a  3-in.  pipe  100  ft.  long  to  carry 
on  2-pipe  work  at  2-lb.  pressure  900  sq.  ft.  or  at  5-lb. 
pressure  1,500  sq.  ft. 

Now  you  and  I  know  of  jobs,  probably,  where  1,200 
to  1,500  ft.  of  surface  have  been  run  on  a  3-in.  main. 

1  have   known   numerous   cases   where   trouble   with 
water-line  developed  and  solely  because  of  the  fact 
that  the  great   number  of  fittings   so   decreased   the 
pressure  at  end  of  supply  main  that  the  straight  drop 
from   supply-pipe   to   water-line   of   boiler   was   some 
inches  less  than  it  should  have  been.     Now  to  illus- 
trate this.    Suppose  there  was  full  1,500  sq.  ft.  on  3-in. 
main.    That  there  were  6  right-angle  elbows,  10  tees, 

2  globe-valves,  and  the  main  was  88  ft.  long.    Accord- 
ing to  note  No.  1,  each  elbow  should  be  counted  as 
increasing  the  length  of  the  pipe  40  diameters.    Then, 
as  the  diameter  is  3  in.  40X3=120  in.  or  the  equal  of 
10  ft.  of  straight  pipe.    There  are  six  of  them,  so  these 
increase  the  friction  equal  to  60  ft.  straight  pipe.  The  10 
tees=--:10X 60=600  diameters,  600X3  in.=l,800  in.-=-12 
in. =150  ft. ;  2  globe-valves=125  diameters  each,  then 
125X2=250  diametersX3  in.=750  in.-f-12  in.=62  ft. 
Instead  of  88  ft.  of  pipe  to  figure  on,  we  have  88+60+ 
150+62=360  ft.  of  pipe.    Now,  according  to  note  No. 
2,  if  pipe  was  300  ft.  long  the  factor  of  .58  was  to  be 
used,  if  400  ft.,  .50.    To  find  our  factor  we  get  the  aver- 
age of  the  two,  or  the  350  ft.  factor,  by  adding  .58+. 50 
=1.08  and  dividing  by  2=.54,  the  proper  factor. 

We  now  multiply  1,500  sq.  ft.  which  could  be  car- 
ried on  100  straight  feet  of  pipe  by  .54  and  find  that 
only  810  ft.  should  have  been  put  on  that  3-in.  main 
under  conditions  of  water-line  intended  by  Mr.  Wolff 
when  the  table  was  made.  Of  course,  this  is  a  most 
unusual  condition  of  fittings,  but  something  similar 

127 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

can  be  found  in  most  every  town  where  there  are  a 
dozen  jobs  of  this  size. 

A  fairly  accurate  guide  for  pipe-sizes  can  be  found 
in  following  table  for  small  installations  say  of  2,000 
sq.  ft.  or  less. 

TABLE  Y. 

To    Find    Pipe- Size    Suitable  for    Varying    Distances    Between 

Supply  or 

Probable  Decrease  in  Pressure  Distance  from  Water-line  of 
of  Steam  in  Ounces  or  Pounds  Boiler  up  to  Main  Supply- 
on  Ordinary  House-Heating  Pipe   Return-End.     Inches. 
Job. 

1  oz.  =    A  Ib.  4 

2  oz.  =    T&  Ib.  6 

4  oz.  —    Yt  Ib.  10  to  12 

8  oz.  =    y2  Ib.  16  to  18 

12  oz.  =    24  lb-  23  to  25 

16  oz.  =  1       Ib.  32  to  33 

24  oz.  =  \Y2  Ib.  46  to  48 

As  in  most  small  jobs  the  areas  will  not  come  out 
exactly  in  correspondence  with  areas  of  commercial 
pipe,  always  take  the  next  larger  area  which  will  fit 
to  commercial-size  pipe. 

In  using  Table  Y,  it  will  be  found  to  be  a  conven- 
ient guide  to  water-lines.  Assume  a  very  low  cellar 
and  a  job  requiring  500  sq.  ft.  of  surface.  How  near 
to  water-line  can  the  return  or  lowest  end  of  supply- 
pipe  be  run  and  have  job  work  with  steady  water- 
line  and  what  size  pipe  will  probably  be  required  for 
single-pipe  circuit? 

We  have  500  sq.  ft.  of  surface.  Then,  by  Table  Y, 
5X1.4=7  sq.  in.  of  area  or  a  3-in.  main,  see  Table  A, 
and  the  return  end  can  be  within  4  in.  of  water-line. 
But  if  there  is  plenty  of  room  and  a  pressure  of  5  Ib. 

128 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

can  be  carried  or  more  upon  occasion,  a  very  small 
pipe  can  be  made  to  work  by  carrying  it  very  high 
above  water-line  of  boiler  at  return-end,  say  48  in., 
the  supply-pipe  starting  the  circuit  of  100  ft.  at,  say 
60  in.  above  water-line  of  boiler.  The  table  says  under 

TABLE  Y. 

Water-Line    of    Boiler    and    Farthest    Point    from    Boiler    of 

Steam-Main. 

To  Find  Area  of  Steam-Main  in  Square 

Inches,   Multiply   Each   100   Sq.   Ft.   of          Probable     Steam 
Radiating    Surface.  Pressure  Re- 

One-Pipe.  Two-Pipe.          quired  at  Boiler. 

1.4  .9  ^Ib.to   lib. 

1.35  .9  lib.  to   2lb. 

1.03  .68  2lb.to    3lb. 

.63  .46  Slb.to   5lb. 

.56  .38  5  Ib.  to  10  Ib. 

.45  .32 

.43  .31 

these  conditions  the  500  ft.  of  heating  surface  multi- 
plied by  .43  will  give  the  size  that  can  be  made  to 
work,  5X -43=2.15  sq.  in.  But  the  area  of  a  2-in.  pipe 
will  have  to  be  taken  because  2.15  is  the  very  smallest 
that  it  will  do  to  use  and  no  commercial-size  pipe  will 
answer  to  a  2.15  sq.  inch  area. 

From  what  has  been  said  it  will  be  seen  that  no 
steamfitter  is  warranted  in  attempting  to  guess  out  a 
job.  No  man  with  sufficient  intelligence  to  be  in  the 
business  at  all,  but  that  is  able  to  lay  out  a  rough 
pencil  or  chalk  diagram  of  the  proposed  job.  From 
this  he  is  able  to  count  up  the  elbows,  tees  and  the 
like  as  well  as  measure  the  actual  length  of  pipe,  fit- 
tings included.  He  can  then  easily  determine  whether 
he  has  more  than  100  ft.  in  length  of  pipe  supposing 
the  ells  and  tees  were  all  in  straight  pipe.  If  he  has, 
he  would  increase  the  size  of  pipe  beyond  table  by 

129 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

at  least  one  commercial  size.  If  he  needed  a  2-in. 
pipe  for  100  ft.  on  an  area  of  2.960  sq.  in.  on  100  ft., 
and  when  fittings  were  added  he  had  200  ft.,  he  would 
use  a  2_^2-in.  pipe,  as  that  is  the  next  larger  commer- 
cial size.  Another  way  to  put  it  would  be  that  under 
the  additional  loss  of  pressure  caused  by  these  fittings 
he  could  not  carry  so  much  surface  on  a  4-in.  differ- 
ence between  water-line  and  lowest  point  of  his  sup- 
ply-pipe. 

Under  the  old  practice  less  attention  was  given  to 
these  questions  than  is  forced  upon  the  fitter  by  the 
new. 


330 


SECTION   XVIII. 


The  discussion  on  pipe  sizes  for  two-pipe  work  and 
single-pipe  work  applies  also  to  all  types  of  steam- 
work.  An  overhead  steam-job  is  sized  for  velocity 
the  same  as  any  other.  There  is  only  one  unfailing, 
never-to-be-forgotten  rule  connected  with  overhead 
work  that  if  overlooked  will  usually  cause  the  water 
to  leave  the  boiler,  viz. :  No  drop-pipe  must  be 
stopped  until  it  is  below  the  water-line  level  of  boiler. 

A  secondary  circuit  can  be  run  half  way  between 
top  supply  and  boiler  or  one  can  be  run  on  several 
floors  if  all  drop-pipes  are  carried  to  basement  and 
enter  main  return  pipe  below  the  water-level  of  boiler. 

Probably  the  overhead  system  is  the  peer  of  all 
heating  systems  where  conditions  permit  or  compel 
its  use. 

If  the  cellar  is  so  low  that  a  circuit  cannot  be  com- 
pleted and  secure  a  steady  water-line,  then  the  over- 
head system  is  all  valuable,  providing  always  that 
every  drop-pipe  is  carried  below  the  water-line  of 
boiler.  If  there  is  one  single  pipe  that  the  fitter  fails 
to  get  into  this  wet  return  below  water-level,  trouble 
will  probably  develop  for  him  all  right,  and  will  con- 
tinue until  the  piping  is  fixed  so  that  the  lower  end  of 
that  drop-pipe  is  below  the  water-level  of  the  boiler. 

It  is  not  necessary  for  the  purposes  of  this  book 
to  go  into  minute  details  of  description  of  pipe-fitting. 
That  is  every-day  practice  for  those  who  are  in  the 
business. 

131 


A    Practical    Manual    of    Steam    and    Hot- Water    Heatin^ 

In  Section  XVII  we  gave  Mr.  Wolff's  table  for 
two-pipe  work.  Table  Z  gives  the  sizes  calculated  by 
Prof.  Carpenter,  for  single  pipe  work,  as  shown  in  his 
book,  "Heating  and  Ventilating  Buildings." 

TABLE  Z. 

Internal  Diameters  of  Steam-Mains  for  a 
Steam  pressure  10  Ib.  above  atmosphere. 
Steam  pressure  0.5  Ib.  above  atmosphere, 

Length  of  Steam-Main  in  Feet. 

Radiating  Surface  Sq.  Ft.  20  40  80 
Diameter  of  Pipe  in  Inches. 

20 0.5  0.5  0.6 

40 0.6  0.7  0.8 

60 0.7  0.8  0.9 

80 0.8  0.9  1.0 

100 0.9  1.0  1.2 

200 1.1  1.3  1.5 

300 1.3  1.5  1.8 

400 1.5  1.7  2.0 

500 1.6  1.9  2.2 

600 1.8  2.0  2.4 

800 2.0  2.3  2.6 

1,000 2.2  2.5  2.9 

1,400 2.5  2.8  3.3 

1,800 2.7  3.2  3.6 

2,000 2.9  3.3  3.8 

3,000 3.4  3.9  4.4 

4,000 3.8  4.3  5.0 

6,000 4.1  4.7  5.4 

8,000 4.4  5.0  5.8 

10,000 4.7  5.3  6.1 


The   above   table   Z   is   computed  by   formulas  for 
diameter  in  inches  in  which  head=318.6  (of  water)  ; 

132 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

quantity  of  steam  discharged  per  minute=9.2  cu.  ft. 
for  100  sq.  ft.  radiating  surface. 

The  table  is  computed  for  straight  pipes  with  water- 
level  in  returns  6  ins.  above  that  in  boiler.    For  other 

TABLE  Z. 


Single-Pipe   System    of  Heating  by  Direct  Radiation, 
frictional  resistance  6  in.  of  water-column, 
frictional  resistrnce  12  in.  of  water-column. 

Length  of  Steam-Main  in  Feet. 

100 

200 

300 

400 

600 

1,000 

Diameter  of 

Pipe  in  Inches. 

0.6 

0.7 

0.8 

0.8 

0.9 

1.2 

0.8 

1.0 

1.0 

1.1 

1.2 

1.6 

1.0 

1.1 

1.2 

1.3 

1.4 

1.8 

1.1 

1.2 

1.4 

1.5 

1.6 

2.1 

1.2 

1.4 

1.5 

1.6 

1.7 

2.3 

1.6 

1.8 

1.9 

2.0 

2.2 

2.9 

1.8 

2.1 

2.3 

2.4 

2.6 

3.5 

2.0 

2.4 

2.6 

2.7 

3.0 

4.0 

2.2 

2.6 

2.8 

3.0 

3.2 

4.2 

2.5 

2.8 

3.0 

3.2 

3.5 

4.5 

2.7 

3.2 

3.4 

3.6 

3.9 

5.0 

3.0 

3.4 

3.7 

3.9 

4.3 

5.5 

3.4 

3.9 

4.2 

4.5 

4.9 

6.5 

3.8 

4.4 

4.7 

5.0 

5.4 

7.0 

3.9 

4.5 

4.9 

5.2 

5.6 

7.2 

4.6 

5.3 

5.8 

6.1 

6.6 

8.5 

5.2 

6.0 

6.5 

6.8 

7.5 

9.7 

5.7 

6.5 

7.1 

7.4 

8.2 

10.5 

6.0 

7.0 

7.5 

7.9 

8.7 

11.3 

6.4 

7.4 

8.0 

8.4 

9.2 

11.9 

resistances  and  steam-pressures,  multiply  the  diameters 
as  given  above  by  following  factors: 

188  A 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

Water-level  in  return  above  boiler. 2  in.     12  in.     18  in. 

Multiply  by    1.25        0.88        0.80 

Steam  pressure  above  atmo- 
sphere  0.5  Ib.       2  Ib.       5  Ib. 

Multiply  by    1.22        1.16        1.09 

It  will  no  longer  answer  to  take  anybody's  table  for 
pipe-sizes  and  put  the  pipe  in  any  old  way. 

Recently  there  have  been  some  very  strenuous  ad- 
vocates of  small  pipe  in  steam-work.  I  have  no  bone 
to  pick  with  them.  They  are  all  right  from  their 
point  of  view  and  with  their  knowledge  behind  their 
point  of  view.  But  with  a  limit  of  2-lb.  pressure  and 
almost  no  knowledge  on  the  part  of  the  trade  of 
velocities  and  volume,  the  members  of  the  trade  at 
large  had  better  stick  to  the  slow  velocity  and  larger 
pipe. 

There  are,  however,  one  or  two  matters  in  regard 
to  the  old  practice  which,  under  the  new  demands 
upon  steam  fitters,  require  suggestion  at  least. 

The  most  important  is  the  habit  of  steam-fitters  in 
both  steam  and  hot-water  piping  of  using  reducing 
tees  and  elbows.  A  tee,  as  we  have  seen,  reduces  the 
pressure  by  friction  the  equivalent  of  60  diameters  of 
pipe  on  a  straight  run.  To  add  to  this  the  friction  of 
a  smaller  pipe  at  the  very  point  where  a  lot  of  strength 
is  needed  anyhow,  is  doubtful  assistance.  It  would 
probably  be  vastly  better  to  continue  the  full  size  of 
pipe  beyond  the  tee  connection  some  distance,  and  use 
a  reducing  coupling  and  thereby  get  nearly  full  value 
of  whatever  strength  or  pressure  was  left  on  the  steam 
or  water. 

Another  is  the  habit  of  using  ordinary  fittings  for 
connections  on  hot-water  jobs.  The  hot-water  job 

134 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

usually  requires  all  the  assistance  it  can  get  to  aid 
the  speed  of  circulation,  and  all  the  power  that  is 
exhausted  in  overcoming  friction  certainly  can  not  be 
regenerated  and  used  to  promote  circulation.  Com- 
mon sense,  applied  to  piping  connections,  would  have 
saved  many  a  job  from  unsatisfactory  performance. 
In  using  the  Table  Y  (see  pages  128-129)  it  must  be 
distinctly  understood  that  it  applies  only  to  a  stand- 
ard friction  condition  equal  to  that  of  100  ft  of 


TABLE  AZ. 

• 

Length  of  Pipe 

Percentage  of  Area 

Percentage  of 

When 

Increase  to  Add  to 

Table  Y  This 

Friction 

Pipe,  to  Make  the 

Will  Carry  and 

of  Fittings 

Friction  Equal 

Have  Friction 

Is  Added. 

Table  Y. 

Equal. 

Feet. 

Per  Cent. 

Per  Cent. 

175 

24 

76 

200 

29 

71 

220 

33 

67 

240 

35 

65 

260 

38 

62 

280 

40 

60 

300 

42 

58 

350 

46 

54 

400 

50 

50 

450 

53 

47 

500 

55 

45 

550 

57 

43 

600 

60 

,     40 

650 

61 

39 

700 

62 

38 

750 

64 

36 

800 

65 

35         - 

850 

66 

34 

900 

67 

33 

1000 

68 

32 

straight  pipe.  Every  elbow,  tee,  globe-valve,  reduc- 
ing-coupling  or  other  friction-creating  agent  must  be 
considered  and  its  equivalent  in  straight  pipe  added 


135 


A    Practical    Manual    of    Steam    and    Hot- Water    Heating 

to  the  actual  measured  length,  or  serious  error  in  the 
area  required  will  surely  arise. 

If  the  pipe  is  uncovered  its  radiating  surface  must 
be  ascertained  and  figured  as  direct  radiation  (see 
Table  EZ).  When  the  length  exceeds  100  ft.,  with 
the  equivalent  length  of  the  fittings  added,  the  results 
found  by  Table  Y  should  be  multiplied  by  one  of  the 
following  factors  given  in  Table  AZ.  Column  A 
expresses  lengths  from  175  ft.  to  1,000  ft.  Col.  2 
shows  the  percentage  of  area  to  be  added  to  the  area 
found  by  Table  Y  in  order  that  the  decrease  in  pres- 
sure shall  remain  the  same  as  that  found  for  100  ft. 
by  Table  Y.  Column  3  shows  what  percentage  of 
radiation  found  by  Table  Y  the  increased  length  of 
piping  will  carry  and  still  maintain  the  distance  be- 
tween water  line  of  boiler  and  lowest  point  of  main  pipe 
intended  or  indicated  by  Table  Y. 

To  the  man  who  desires  to  do  good  work  in  steam- 
heating  houses,  no  more  important  tables  will  be  pre- 
sented than  these  in  regard  to  the  sizing  of  pipes. 
The  use  of  the  tables  is  as  follows : 

Assuming  that  on  a  simple  job  as  illustrated  by 
Fig.  12,  the  total  amount  of  the  required  radiation, 
including  surface  of  the  main  itself,  is  found  to  be 
345  sq.  ft.,  and  the  cellar  is  found  to  be  so  low  that 
from  point  x  on  the  bottom  of  the  main,  to  the  water 
line  of  the  boiler  selected  to  use,  only  4  inches  can  be 
secured.  It  is  desired  to  know  what  size  main  to  use 
if  a  single  pipe-circuit  job  is  put  in,  also  what  size 
pipe  will  be  required  for  a  two-pipe  job. 

From  Table  Y  we  learn  that  for  only  4  inches  drop, 
each  100  ft.,  and  fraction  of  100  ft.  of  radiation,  must 
be  multiplied  by  1.45  to  find  the  area  of  pipe  neces- 

1M 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

sary  for  a  one-pipe  job,  and  for  a  two-pipe  job  the 
total  radiation  should  be  multiplied  by  0.97  to  get  the 
correct  area  for  100  ft.  of  straight  pipe. 

We  look  at  the  sketch  and  notice  that  on  a  single- 
pipe  circuit  there  are  9  elbows  above  water-line  of 
boiler,  and  6  tees.  We  may  also  find  the  actual  meas- 
ured length  of  the  proposed  circuit  to  be,  say,  92  ft. 
It  is  evident  that  in  this  case  fittings  must  cut  con- 
siderable of  a  figure.  We  first  find  out  what  size  of 
•pipe  would  be  required  to  carry  the  345  sq.  ft.  of  radi- 
ation if  the  pipe  had  no  fittings  and  was  perfectly 
straight.  We  therefore  multiply  the  300  ft.  and  the 
45/100  ft.  by  1.45  to  get  the  area  of  main  for  single- 
pipe  circuit  3.45X1-45=5  sq.  in.  The  nearest  com- 
mercial-size pipe  of  this  area  is  a  2^-in.  pipe.  But 
this  is  for  100  ft.  of  straight  pipe.  See  Table  A.  Page  12. 

We  must  find  out  how  many  feet  of  straight  pipe 
these  fittings  will  equal  and  add  it  to  the  92  ft.  of 
measured  length  in  the  lay-out.  Each  2^2-in.  elbow 
is  the  equivalent  of  8  ft.  2  in.  of  2^2-in.  pipe  and  each 
tee  of  12  ft.  6  in.  Then  the  9  elbows  are  equivalent  to 
73^  and  the  6  tees  to  75  ft.  more.  The  total  length 
then  that  must  be  taken  into  account  is  92+73+75= 
240  ft.  Table  AZ  states  that  the  area  in  the  pipe  must 
be  increased  35  per  cent  to  carry  240  ft.  of  length  and 
provide  same  drop  as  for  100  ft.  length.  35  per  cent 
of  5  is  1.75;  then  5+1.75=6.75  sq.  in.  area  that  must 
be  provided.  This  area  requires  that  a  3-in.  pipe  be 
used  if  a  steady  water-line  is  to  be  maintained. 

If  the  height  of  the  cellar  would  permit  a  distance 
of  18  in.  between  point  x  and  the  water-line  of  boiler, 
instead  of  multiplying  by  the  factor  1.45  the  radiation 
should  be  multiplied  by  0.68.  From  Table  CZ  it  will 

137 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

be  found  that  the  fittings  are  equivalent  to  a  length  of 
125  ft.  of  pipe  to  be  added  to  the  92  ft.  of  measured 
length,  or  a  total  length  of  217  ft.  The  area  found  to 
be  needed  by  Table  Y  for  345  sq.  ft.  of  radiation  with 


F!,.   12. 


Fig.  12. 

an  18-in.  drop  is  2.346  sq.  in.  Table  AZ  gives  the  in- 
crease in  area  necessary  to  equalize  220  ft.  in  length 
with  100  ft.  as  0.33  per  cent.  When  this  percentage 

138 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

is  added  we  have  the  required  area  as  3.12  sq.  in.  or 
the  area  of  a  2-in.  pipe.  In  the  same  manner  we  would 
find  the  area  that  should  be  used  if  the  head-room  per- 
mitted the  main  to  have  a  drop  of  4  it.  It  will  be 
found  to  require  1^-in.  pipe  for  the  main  if  a  48-in. 
drop  can  be  had.  A  main  pipe  should  never  be  used 
of  less  area  than  a  lj/2-in.  pipe. 

These  illustrations  very  clearly  show  that  it  is  of 
the  utmost  importance  to  the  fitter  that  he 
should  know  what  distance  can  be  secured  between 
the  low  point  of  the  proposed  main  and  the  water- 
line  of  the  boiler  to  be  selected.  In  fact,  an  intelligent 
selection  of  the  piping  layout,  or  of  a  properly  propor- 
tioned steam-boiler  cannot  be  made  without  this  in- 
formation. 

The  importance  of  reaming  the  ends  of  every  pipe 
can  be  seen  in  the  light  of  this  discussion.  For  in- 
stance, the  burr  which  is  often  left  when  pipe  is  cut 
not  only  produces  a  considerable  amount  of  friction, 
but  produces  an  actual  reduction  in  the  available  area 
of  the  pipe  itself. 


139 


SECTION    XIX. 


In  order  to  bring  out  this  close  connection  between 
the  low  point  of  main  and  the  water-line  of  boiler,  and 
the  size  of  main  that  can  be  used;  the  necessity  also 
of  knowing  the  velocity  at  which  the  steam  is  to  move, 
before  selecting  the  pipe-size  for  the  main,  or  the 

TABLE   BZ. 

Number  of  Ft.  of  Radiation  Main  May  Carry  by  the  Rule. 

J.  L.       Cleve- 


Size  Pipe. 

Monroe. 

Mott. 

land. 

2   in  

300 

200 

400 

2]/2  "   

500 

400 

625 

3    "  

750 

700 

962 

3^  "  

1,075 

1,060 

1,225 

4    "  

1,400 

1,590 

1,600 

±l/2   "       

1,900 

2,272 

2,025 

5    "   

2,400 

3,120 

2,500 

6    "  

4,000 

5,440 

3,600 

7    "  

5,500 

8,550 

4,900 

8    "   

7,000 

12,556 

6,400 

10    "  

12,000 

25,300 

10,000 

make  or  type  of  boiler  to  be  used,  a  summary  of  the 
illustration  just  given  will  be  useful. 

We  have  found  that,  in  this  one  selected  case,  three 
sizes  of  pipe  can  be  used.  But  each  requires  a  differ- 
ent distance  between  low  point  of  main  and  the  water- 
line  of  boiler.  Thus: 

Can  use  3-in.  pipe  and  have    4-in.  drop. 

Can  use  2-in.  pipe  and  have  18-in.  drop. 

140 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

Can  use  lj^-in.  pipe  and  have  48-in.  drop. 

The  tremendous  import  of  the  point  brought  out, 
and  its  value  to  the  trade  can  be  seen  by  the  most 
casual  inspection  of  the  following  Table  BZ,  which 
gives  the  pipe  sizes  suggested  by  nine  well-known 
authorities,  or  in  use  in  certain  localities  by  a  num- 
ber of  high-class  fitters.  These  nine  have  been  select- 
ed in  order  that  practically  every  section  of  the  coun- 
try where  considerable  work  in  steam-heating  is  done 
may  have  a  fairly  representative  showing.  The  selec- 


Number 

TABLE  BZ. 

of  Ft.  of  Radiation  Main  May 

Carry  by  the  Rule. 

St. 

C.  B. 

Baldwin. 

Chicago. 

Mills. 

Whitelaw. 

Louis. 

Thompson. 

350 

500 

360 

300 

590 

314 

460 

750 

560 

500 

1,240 

706 

675 

1,000 

800 

900 

1,900 

962 

850 

1,250 

1,000 

1,450 

2,500 

1,250 

1,100 

1,500 

1,400 

2,000 

3,900 

1,590 

1,350 

2,000 

1,800 

2,500 

4,000 

1,963 

2,000 

3,000 

2,200 

3,000 

6,900 

2,827 

3,600 

4,000 

3,300 

4,500 

10,000 

3,848 

5,000 

5,500 



7,000 

13,500 

5,026 

6,500 

7,000 

..... 

12,000 

19,500 

7,854 

9,800 

10,000 



16,000 

31,000 

tion  includes  the  following  authorities  and  local  city- 
practices — William  Monroe;  J.  L.  Mott;  W.  J.  Bald- 
win; John  H.  Mills;  Norman  Whitelaw;  C.  B.  Thomp- 
son, in  "Plumbers'  Trade  Journal" ;  a  Cleveland,  O., 
Rule;  a  Chicago,  111.,  Rule;  a  St.  Louis,  Mo.,  Rule. 
For  a  more  extended  list  see  "Sizes  of  Flow  and 
Return  Steam  Mains,"  published  by  "Domestic "En- 
gineering" in  1909. 

141 


"Domestic  Engineering"  Cartoon  on  "The  Intricicies  of  Boiler-Rating"  No.  IX. 


TRUE      HEATING     VALUES 


The   Steam- Fitter's   Choice      Will    He   Make   the   Lighthouse? 

The   Steam -Fitter's   Choice.      Will    He    Make   the   Lighthouse? 


142 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

After  looking  over  this  list,  which  one  would  be 
chosen  for  a  job  where  the  utmost  drop  to  be  ob- 
tained between  water  line  of  boiler  and  low  point  of 
main  circuit  was  seven  inches?  A  decision  would  be 
fully  as  much  of  a  guess  as  any  of  the  old  guess-work 
rules  for  selecting  radiation. 

The  differences  shown  in  the  above  table  is  a  very 
rriarked  example  to  show  the  need  of  instruction  to  the 
trade  in  general  in  the  use  of  piping. 

The  reader  who  has  followed  the  discussion  to  this 
point  can  readily  understand  that  no  one  would  be 
justified  in  stating  that  either  of  the  nine  rules  is  in 
error  all  the  way  through. 

That  some  radical  changes  in  velocities  occur  in 
nearly  every  column  is  perfectly  evident.  It  may 
seem  that  the  radiation  provided  for  a  3-in.  main  in 
Col.  2,  if  correct,  must  prove  that  the  1,900  ft.  per- 
mitted by  Col.  9  for  same  size  of  pipe  is  badly  off. 
But,  as  has  been  shown,  the  question  of  velocity  to  a 
very  considerable  extent  determines  the  size  of  pipe 
needed  to  deliver  a  given  number  of  pounds  of  steam 
to  a  given  point  in  a  stated  period  of  time.  Then,  again, 
as  has  been  shown,  the  pressure  at  the  boiler  has  a  bear- 
ing. Before  condemning  Col.  9  as  certainly  wrong,  let 
us  analyze  both  and  see  if  possibly  each  is  not  correct. 

Assuming  that  the  steam  in  each  case  is  to  reach 
the  radiators  at  a  pressure  that  shall  average  212 
deg.  F.  in  the  radiators,  and  that  the  radiators  shall 
emit  in  both  cases  227  b.  t.  u.  per  sq.  ft.,  the  tempera- 
ture of  the  room  being  at  70  deg.  (212—70=142.  142 
XL 6=227  B.  t.  u.),  let  us  examine  both  suggestions. 

Under  these  conditions  the  700  ft.  will  call  for  158,- 
900  B.  t.  u.  per  hour,  or  about  165  Ib.  of  steam,  each 

143 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

pound  of  which  will  fill  26.4  cu.  ft.  per  hour  or  1.21 
cu.  ft.  of  area  per  second.  With  a  speed  of  25  ft.  per 
second,  the  area  required  to  furnish  the  needed  steam 
is  found  in  3-in.  pipe. 

The  1,900  ft.  upon  the  same  statement  of  conditions 

TABLE  CZ. 

Length  of  straight  pipe  which  equals  the  friction  of  various 

fittings.     Actual  diameters  of  pipe  taken  for  this  table. 

Size  of  Pipe  Each  Tee  Equal 

Fitting  in  to  Straight  Pipe 


Inches. 

Ft. 

In. 

y2  

3 

2 

y4  

4 

2 

i   

5 

2 

\y4  

6 

10 

V/2    

8 

2    

10 

4 

%y2  

12 

4 

3    

15 

4 

31^   

17 

8 

4    

20 

2 

4^  

22 

6 

5    

25 

2 

6    

30 

4 

7    

35 

2 

8    

39 

11 

9    

45 

10    

50 

12    

60 

•• 

will  emit  431,300  B.  t.  u.  per  hour,  requiring  447  Ib. 
of  steam  per  hour,  or  3.25  cu.  ft.  per  second.  With 
a  velocity  of  a  trifle  over  66  ft.  per  second,  a  3-in.  pipe 
would  be  sufficiently  large,  providing  that  the  total 


144 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

friction  did  not  exceed  that  on  a  pipe  100  ft.  long  and 
without  elbows,  tees,  or  other  friction-creating  items. 
For  a  complete  method  of  figuring  out  these  velocities 
Section  XV  of  this  series  will  repay  the  reader's  careful 
study. 

TABLE  CZ. 

Length  of  straight  pipe  which  equals  the  friction  of  various 
fittings.     Actual  diameters  of  pipe  taken  for  this  table. 


Each  Elbow  Equal 
to   Straight  Pipe. 

Each    Coupling 
Equal  to  Straight 
Pipe. 

Each  Valve  Equal 
to  Straight  Pipe. 

Ft.           In. 

Ft. 

In. 

Ft. 

In. 

2               2 

1 

1 

3 

2 

2                8 

1 

4 

4 

2 

3                6 

1 

9 

5 

2 

4                7 

2 

y/2 

6 

10 

5                5 

2 

ll/2 

8 

6              11 

3 

5l/2 

10 

4 

8                2 

4 

1 

12 

4 

10                2 

5 

1 

15 

4 

11                9^ 

5 

10 

17 

8 

13                5 

6 

7 

20 

2 

15 

7 

6 

22 

6 

16              10 

8 

5 

25 

2 

20                2 

10 

1 

30 

4 

23                5 

11 

8 

35 

2 

26                8 

13 

4 

39 

11 

30 

15 

45 

33              4 

17 

50 

40 

20 

60 

•• 

But  if  the  total  length  of  pipe,  including  the  friction 
of  the  fittings,  exceeds  100  ft.,  how  will  you  proceed 
if  the  drop  is  7  in.,  for  instance?  With  the  conditions 
named,  how  are  you  to  tell  the  distance  needed  be- 

145 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

tween  water-line  of  boiler  and  drop  point  of  piping? 
There  is  nothing  plainly  stated  in  the  tables  that 
gives  the  slightest  clue  to  these  points  which  are  of 
vital  importance  to  the  fitter  who  intends  to  do  good 
work  intelligently  and  not  by  guess. 

Now  take  these  same  assumed  conditions  and  the 
same  amounts  of  radiation  and  see  what  can  be  done 
with  them  by  the  aid  of  Table  Y,  using  the  same  700 
and  1,900  ft.  of  radiation  and  securing  a  3-in.  pipe. 

For  a  two-pipe  job,  we  find  that  the  7  hundreds 
multiplied  by  the  factor  .90  calls  for  a  3-in.  pipe  as 
nearest  commercial  size.  The  19  hundreds  if  multi- 
plied by  the  factor  .32  also  calls  for  a  3-in!  pipe.  But 
the  Table  Y  also  tells  something  more  about  the  case. 
It  tells  that  with  the  3-in.  pipe  for  the  700  ft.  one  can, 
if  needed,  bring  the  lowest  point  of  the  main  to  with- 
in from  6  to  9  in.  of  the  water  line  of  boiler.  If,  how- 
ever, the  3-in.  pipe  is  used  for  the  1,900  ft.  of  radia- 
tion, there  must  be  at  least  33  in.  between  the  two 
points  mentioned.  There  is  nothing  stated  in  the 
tables  usually  found  in  trade  catalogs  to  guide  one  in 
these  things.  If  one  needs  to  use  a  single-pipe  circuit, 
Table  Y  furnishes  all  the  needed  data  for  the  proper 
size.  Table  Y  and  Table  AZ  will  practically  answer 
every  question  that  will  arise  in  regard  to  steam- 
mains  in  any  house-heating  job. 

By  the  aid  of  these  two  tables  it  is  possible  to 
reconcile  all  the  apparently  wild  suggestions  for  pipe- 
sizes  that  are  published  from  time  to  time  in  the  trade 
magazines. 

It  is  hoped  that  this  dicussion  may  help  to  make 
clear  to  my  readers  this  hitherto  perplexing  question. 
The  one  thing  never  to  be  forgotten  in  studying  this 

146 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

pipe-question,  is  that  the  standard  of  pipe-sizing  is 
100  ft.  of  straight-pipe  friction.  If  fittings  are  used, 
the  length  of  pipe  which  the  fittings  equal  in  friction 
must  be  added.  As  perhaps  some  who  may  use  this 
book  may  not  have  the  time  or  inclination  to  figure  out 
for  themselves  the  values  in  straight  pipe  of  the  va- 
rious fittings  most  often  used  in  steam  fitting,  Table  CZ 
is  given  for  their  benefit. 

The  importance  of  this  table  to  any  steam-fitter 
in  the  -exceedingly  vital  matter  of  correct  piping  must 
be  apparent  to  the  most  casual  reader. 

It  seems  rather  strange,  however,  that  although  the 
first  one  of  the  American  writers  on  the  subject  of 
steam  heating  called  attention  to  this  matter  of  fric- 
tion in  the  pipes,  and  as  early  as  about  1870  such  al- 
lowances were  in  use  by  the  best  grade  of  engineers 
in  Boston  and  New  York,  the  working  steam-fitter 
of  that  day  seems  to  have  had  little  or  no  knowl- 
edge of  the  matter.  And  for  that  reason,  perhaps, 
the  knowledge  does  not  seem  to  be  at  all  general  to 
this  day. 


147 


Section  XX. 


The  first  steam-heating  of  buildings  to  be  applied 
in  this  country  originated  with  the  firm  of  Walworth 
&  Nason  of  Boston,  Mass.  The  first  building  in 
America  to  be  steam-heated,  using  small  wrought- 
iron  pipe  to  convey  the  steam,  was  the  building  in 
Boston  then  known  as  the  Eastern  Exchange  Hotel. 
This  was  completed  about  1845  or  only  65  years  ago 
at  this  writing.  The  early  heating  of  the  rooms  was 
accomplished  entirely  by  means  of  pipe-coils.  Later, 
various  forms  of  cast-iron  radiators  came  into  use. 
The  names  given  to  these  as  generally  applied  by  the 
trades-people  clearly  indicates  their  appearance.  There 
were  the  "Ox-bow,"  the  "Wash-board,"  the  "Bars," 
and  others  in  cast-iron.  A  very  popular  radiator  in 
some  sections  of  New  England  at  that  time  was 
built  of  sheet-iron.  This  radiator  was  bolted  in  such 
a  way  that  the  steam  passed  up  and  down  quite  in  the 
same  manner  that  it  passes  in  a  hot-water  radiator  of 
today.  In  general  appearance  this  radiator  resembled 
a  bed-mattress,  and  was  usually  called  the  "mattress 
radiator"  by  the  trade. 

It  was  not  until  1862  that  the  Nason  radiator  made 
its  appearance.  This  radiator  was  built  of  pipes 
screwed  into  a  cast-iron  base  and  so  adjusted  that 
each  pipe  and  the  base  for  it  contained  exactly  one 
square  foot  of  superficial  surface.  This  radiator  was 

148 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

the  first  to  be  constructed  on  strictly  scientific  lines 
and  I  think  it  can  be  fairly  stated  that  all  radiator- 
ratings  in  use  today  in  this  country  are  primarily 
based  upon  the  Nason  radiator.  The  ratings  of  radia- 
tors will  be  explained  more  fully  in  a  later  chapter. 
The  great  thinkers  and  engineers  of  those  early  days 
who  gave  their  lives  to  the  development  of  the  heat, 
ing  industry,  comprised  many  notable  men,  some  of 
whom  are  herewith  enumerated : 

Joseph  Nason,  who  with  J.  J.  Walworth,  created  the 
firm  of  Walworth  &  Nason,  afterwards  merged  into 
the  great  manufacturing  concern  known  as  The  Wal^ 
worth  Manufacturing  Co. 

Miles  Greenwood,  of  Cincinnati,  who  invented  the 
arrangement  of  a  nest  or  coil  of  upright  pipes  con- 
nected by  return  bends. 

Thomas  Tasker,  of  Philadelphia,  known  as  the  first 
to  introduce  the  closed  system  returning  the  water  of 
condensation  to  the  boiler.  Professor  Mapes,  of  New 
York,  who  invented  the  first  reliable  steam-trap. 

Mr.  Gold,  of  Connecticut,  whose  invention  of  the 
Gold-pin  radiator  changed  the  steam-heating  practice 
of  the  entire  trade  in  many  respects.  Robert  Briggs, 
who  "established  the  characteristic  shapes  and  dimen- 
sions universally  adopted  for  the  globe-valves  and  for 
the  fittings  or  couplings  of  the  tubes." 

Of  this  brilliant  and  capable  group  of  men  the  only 
one  to  place  in  print  any  considerable  amount  of  the 
great  fund  of  knowledge  he  had  gained  by  study  and 
experience  is  Robert  Briggs.  In  the  "Proceedings 
of  the  Institution  of  Civil  Engineers"  are  to  be  found 
many  things  presented  by  him.  About  1882  some  of 
these  papers  were  collected  and  published  by  D.  Van 
Nostrand  Co.,  of  New  York. 

149 


A    Practical    Manual    of    Steam    and    Hot- Water    Heating 

Mr.  Briggs  became  associated  with  Walworth  and 
Nason  in  1846  and  therefore  can  be  clearly  called  the 
most  competent  authority  possible,  to  decide  as  to  the 
friction-demands  of  the  fittings  which  are  still  made 
upon  the  "characteristic  shapes  and  dimensions"  es- 
tablished by  him. 

It  is  from  the  data  furnished  by  Mr.  Briggs  that 
the  Table  CZ  has  been  compiled.  It  seems  probable 
to  the  writer  that  one  of  the  reasons  that  the  trade 
at  large  has  not  become  conversant  with  the  tre- 
mendous effect  for  trouble  that  the  friction  of  fittings 
may  have  on  a  given  job,  is  because  the  few  authori- 
ties who  have  given  the  matter  attention  have  quite 
generally  led  up  to  it  through  formulae  that  the  av- 
erage working  steam-fitter  did  not  fully  comprehend. 
Another  reason  possibly  is  that  the  great  majority  of 
the  steam-fitters  of  the  present  day  have  secured  their 
notions  as  to  the  detail  of  the  work  from  trade  cata- 
logs, traveling  salesmen  who  might  or  might  not 
have  some  engineering  skill,  and  to  a  very  large  de- 
gree from  the  "lay-outs"  which  different  manufactur- 
ers of  boilers  or  radiators  were,  until  within  a  very 
few  years,  prone  to  furnish  to  the  purchasers  of  their 
material. 

Naturally,  if  the  manufacturer  or  his  engineer  un- 
derstood all  about  the  effect  of  fittings  on  pipe  sizes 
he  did  not  explain  the  thing  to  the  customer,  rarely 
saying  anything  more  than  that  "the  pipe  sizes  as  giv- 
en must  not  be  changed,  or  any  changes  made  in  the 
connections  without  consultation  with  the  one  who 
furnished  the  plans." 

From  1862  to  about  1892,  the  practice  of  furnishing 
piping  plans  to  any  one  who  would  buy  boilers  was 

150 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

the  universal  habit  in  this  country.  In  this  way  men 
who  were  totally  incompetent  for  the  work  came  in 
time  to  the  doing  of  the  plan-making  work  for  some 
of  the  manufacturers.  That  the  results  were  not  more 
disastrous  than  they  often  proved  is  a  matter  of  wonder 
to  some  of  those  who  look  back  upon  those  days  from 
the  standpoint  of  present  knowledge. 

It  is  with  full  knowledge  of  those  days  in  mind 
that  the  writer  is  giving  so  much  space  to  this  sub- 
ject of  pipe  and  fittings.  It  is  not  to  be  wondered  at, 
I  think,  that  the  trade  at  large  is  not  familiar  with 
this  most  important  thing  in  regard  to  piping,  when 
one  looks  up  the  trade-papers  for  the  past  30  years 
and  finds  what  a  very  small  amount  of  information 
given  in  plain  English  and  clearly  stated  can  be  found 
in  them,  information  as  to  piping  resistance  and  the 
like. 

In  1906,  a  gentleman  from  Montevideo,  Minn.,  ad- 
dressed a  letter  to  "Domestic  Engineering"  asking  for 
information  as  to  pipe-sizes.  Thirty  of  the  best  fitters 
and  engineers  in  the  country  answered  the  inquiry. 

Not  one  of  them  gave  out  figures  that  in  all  respects 
agreed  with  any  other  one!  It  would  be  totally  im- 
possible to  find  out  from  any  or  all  of  these  30  answers 
how  to  bring  all  these  conflicting  sizes  to  one  common 
basis  and  from  that  base  to  find  the  velocity  required 
by  each,  the  probable  drop  in  pressure  in  order  to 
locate  height  of  main  above  the  water-line,  or  what 
percentage  to  add  for  fittings.  It  is  perfectly  evident 
from  the  replies  that  some  of  the  writers  had  these 
things  in  mind,  but  no  one  seemed  inclined  to  explain 
them.  Out  of  the  30,  one  only  gave  a  statement  of 
the  results  in  pipe-sizes  required  to  supply  25  Ib.  steam 

151 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

through  100  ft.  of  pipe  at  four  different  velocities. 
But  this  one  gave  no  hint  of  the  needed  increase  in  pipe 
size  if  the  fittings  taken  off  the  main  increased  the 
friction  to  equal  another  100  ft.  if  same  drop  or  dis- 
tance between  main  and  water-line  ivas  to  obtain. 

Four  lay  stress  upon  velocity,  but  give  nothing  to 
enlighten  the  inquirer  as  how  to  determine  in  advance 
what  the  probable  velocity  will  be  in  any  given  case. 
Four  others  pay  considerable  attention  to  pressure  at 
boiler,  but  give  no  adequate  advice  in  regard  to  how 
this  may  affect  the  size  of  the  main  pipe.  One  writer 
give  a  comprehensive  list  of  pipe  sizes  suggested  by 
a  number  of  authorities,  some  of  which  are  made  use 
of  in  Table  BZ,  in  connection  with  others  in  the  pres- 
ent discussion,  but  fails  to  reconcile  the  differences 
between  the  figures  beyond  showing  the  great  differ- 
ences in  velocities.  One,  only,  states  the  back-pressure, 
saying  "that  his  tables  are  calculated  on  12-in.  back- 
pressure." One  gives  a  fine  description  of  the  relative 
value  of  drop-distances,  but  does  not  explain  how  these 
distances  are  to  be  obtained  by  the  fitter.  One  gives 
Wolfs  table  of  factors  for  decreasing  the  radiation  for 
increased  length  of  main,  but  fails  to  mention  fittings 
in  any  way.  Out  of  the  30  answers,  only  3  make 
special  mention  of  the  importance  of  the  friction  of 
fittings,  and  of  these,  one  goes  a  little  farther  than 
the  rest,  and  embodies  his  explanation  in  a  sentence 
of  14  words.  After  placing  fittings  as  the  third  im- 
portant factor  out  of  six  mentioned  he  disposes  of 
it  thus :  "If  a  number  of  fittings  are  on  the  pipe  I  allow 
somewhat  larger  sizes."  Of  the  other  two  who  spec- 
ially refer  to  fittings  one  says  very  truthfully.  "Every 
bend  and  angle  produces  friction."  He  refrains  from 

152 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

giving  the  (Montevideo,  Minn.,  man,  or  others,  any 
specific  information  as  to  the  method  of  finding  out 
how  much  this  friction  might  be  or  how  to  provide 
for  it  in  the  pipe. 

That  this  matter  of  pipe  for  mains  is  considered  of 
paramount  importance  is  shown  by  the  appointment  by 
the  American  Society  of  Heating  &  Ventilating  En- 
gineers in  1906  of  a  very  able  committee  to  secure 
data  from  members  of  the  society  upon  standard  sizes 
of  steam  and  return-mains."  This  committee  made 
its  final  report,  it  is  said,  in  1907.  In  conclud- 
ing their  report  this  committee  said :  "In  regard  to 
the  recommendation  of  a  'standard',  their  investiga- 
tions have  led  them  to  the  conclusion  that  the  use  of 
such  a  velocity  as  will  require  a  difference  in  pressure 
of  not  more  than  one  ounce  to  100  ft.  in  straight  pipe 
to  maintain  it,  represents,  as  near  as  they  can  at  the 
present  time  ascertain,  the  best  average  practice  in 
proportioning  the  sizes  of  steam  and  return-mains." 
This  committee  prepared  a  table  of  the  highest,  lowest 
and  average  sizes,  from  the  data  received  by  them  from 
the  members  of  the  society.  From  this  table,  which 
is  only  partially  reproduced  here,  just  one  size  will 
be  taken  to  illustrate  the  danger  of  taking  any  table, 
which  is  ready-made,  as  a  guide  in  selecting  a  main 
for  house-heating. 


153 


FROM  THE  REPORT  OF  COMMITTEE  OF  THE 

SOCIETY  OF  HEATING  AND  VENTI- 

LATING ENGINEERS. 

TABLE  DZ. 

"Maximum  amount  of  radiation  permitted  on  low-pres- 
sure steam-main  in  plants  of  moderate  size,  or  those  not 
having  over  100  ft.  of  main." 

Condensed  from  an  article  in  "Domestic  Engineering." 
Size  Pipe. 

1       in. 


Highest. 

Lowest. 

Average. 

100 

40 

59 

125 

75 

94 

250 

126 

171 

400 

286 

335 

700 

500 

594 

1280 

800 

994 

1600 

1100 

.  1407 

2560 

1500 

1971 

The  average  in  above  table  is  said  to  have  been 
made  up  from  all  the  data  supplied  to  the  committee, 
and  probably  is  the  fairest  presentation  of  the  average 
practice  of  the  highest  type  of  steam-fitters  in  this 
country  in  1906  that  can  be  procured. 

Assume  one  of  these  new  types  of  houses  patterned 
somewhat  after  the  bungalow  of  the  far  west,  which  calls 
for  8  radiators  having  a  total  of  332  sq.  ft.  all  on  one 
floor.  Mr.  Fitter  looks  at  the  Society's  table  and  find- 
ing that  it  gives  a  leeway  between  high  and  low  of  114 
ft.,  with  an  average  about  what  his  job  calls  for,  de- 

154 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

cides*  to  use  a  2-in.  main  for  a  two-pipe  lay-out.  He 
finds  that  the  total  run  of  pipe  will  measure  70  ft.  As 
this  is  30  ft.  less  than  the  length  upon  which  the  table 
is  said  to  be  based,  he  feels  very  confident  that  the  job 
wjll  be  perfect,  and  will  not  show  a  greater  decrease 
in  pressure  than  one  ounce. 

When  the  time  comes  to  put  it  up,  he  decides  to 
make  sure  that  no  trouble  with  water-line  being  un- 
steady shall  occur,  and  so  he  runs  the  pipe  full  size  for 
the  entire  70  ft.  The  cellar  is  none  too  deep,  and  he 
finds  he  has  not  a  large  drop,  but  this  does  not  seem 
dangerous,  considering  that  30  ft.  In  time  the  job 
is  tested  out.  Then  begins  trouble  for  Mr.  Fitter, 
and  Mr.  Boiler-maker,  and  Mr.  Owner.  By  the  time 
a  2-lb.  pressure  shows  on  the  boiler-gage  the  water- 
line  is  jumping  furiously.  The  reason  is  not  hard 
to  find  for  the  man  who  has  at  his  command  tables, 
Y,  AZ,  and  CZ.  From  table  CZ  he  finds  that  the  eight 
2-in.  tees  on  the  main  require  82  ft.  8  in.  of  straight 
2-in.  pipe  to  equal  their  friction.  The  9  elbows  re- 
quire 62  ft.  more,  so  that  he  has  a  total  length  of  215 
ft.  instead  of  70  ft.  to  reduce  pressure.  By  table  AZ 
he  finds  that  with  220  ft.  in  length  he  can  only  carry 
67  per  cent  of  either  amount  given  in  the  Society's 
table  and  maintain  the  "standard"  loss. 

This  means  then  that  his  method  of  piping,  while 
giving  all  the  relief  possible,  still  has  produced  such 
a  loss  in  pressure  by  fitting-friction  that,  under  the 
highest  estimate  of  any  fitter  reporting  to  the  com- 
mittee, not  over  268  sq.  ft.,  could  have  been  used  and 
maintain  the  "standard"  pressure,  while  the  average 
of  them,  whose  practice  he  thought  he  was  taking, 


155 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

would  only  use  224  sq.  ft.,  on  220  ft.  length  of  straight 
pipe,  or  its  equivalent  in  friction. 

If  the  fitter  had  started  his  job  from  Table  Yj  and 
when  he  had  it  sketched  out  roughly,  so  that  he  could 
count  up  the  fittings  on  the  main,  had  added  to  the 
first  measured  length  the  equivalent  length  as  found 
by  Table  AZ,  he  would  have  soon  found  that  in  order 
to  maintain  the  "standard"  pressure  at  return  end  of 
piping  that  he  must  increase  the  area  of  the  main  33 
per  cent.  With  this  much  added  the  Society's  rule 
in  this  case  would  have  been  correct. 

Neglect  on  the  part  of  the  fitter  to  count  the  heat- 
ing surface  contained  in  the  surface  of  the  piping  is  an 
almost  universal  habit  among  fitters  who  do  not  give 
their  entire  time  to  the  business,  and  with  some  who 
do,  I  regret  to  state.  This  neglect  often  causes  serious 
trouble  to  the  man  who  was  so  foolish  as  to  neglect 
to  take  into  his  figuring  probable  loss  from  this 
source.  For  instance,  in  the  case  just  illustrated,  with- 
out taking  the  loss  from  this  source  into  the  account 
at  all,  we  found  that  the  2-in.  pipe  was  overloaded  107 
sq.  ft.  But  in  order  to  get  the  full  amount  of  the 
trouble  that  would  be  coming  to  the  fitter,  we  must 
add,  to  the  332  ft.  of  radiation  he  had  put  in,  the  117 
sq.  ft.  of  heating-surface  which  the  pipe  itself  con- 
tained. With  this  added  the  simple  fact  is  that  the 
fitter  was  trying  to  maintain  "standard"  pressure  for 
449  sq.  ft.  of  surface,  on  215  ft.  of  2-in.  pipe- friction ! 
This  being  over  10  per  cent  more  radiation  than  the 
table  prepared  by  the  committee  of  the  Society  of  Heat- 
ing and  Ventilating  Engineers  claimed  to  be  the  high- 
est permissible  to  be  carried  by  a  2-in.  pipe  for  100  ft. 
The  number  of  square  feet  of  surface  which  the  meas- 

156 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 


tired  length  of  any  given  size  of  pipe  in  com- 
mon use  will  contain  can  be  figured  from  Table  EZ. 
This  table  also  shows  the  actual  internal  area  of 
the  different  sizes  of  pipe.  In  cases  where  very  close 
figuring  for  water-line  is  required,  this  table  can  be 

TABLE  EZ. 

Table  of  Important  Dimensions  of  Steam-Pipe  in 

Steam-Heating. 
Length  of  Pipe  in  Ft. 


Normal 

Per  Sq.  Ft. 

of 

Actual  Internal 

Diameter. 

External  Surface. 

Area  in  Sq.  In. 

V-2  in. 

4ft.    6 

in. 

.3048 

'6A  " 

3  "     8 

" 

.5333 

1      " 

3   "     0 

re 

.8626 

1/4  " 

2  "     4 

a 

1.496 

iH  " 

2  "     0 

«« 

2.038 

2       " 

1  "     8 

(t 

3.356 

2^   " 

1  "     4 

ii 

4.784 

3 

1  "     0 

<( 

7.388. 

3^   " 

0  "  11 

t( 

9.887 

4       " 

0  "  10 

a 

12.730 

4/2     " 

0  "     9 

tt 

15.961 

5 

0  "     8 

(C 

19.990 

6       " 

0  "     7 

tt 

28.888 

7       " 

0  "     6 

" 

38.738 

8 

0  "     5^ 

" 

50.04 

9 

0  "     4l/2 

" 

62.73 

10        " 

0  "     4 

(( 

78.839 

12        " 

o  "    y/2 

" 

113.098 

14       " 

0  "     3 

" 

159.485 

used  in  the  place  of  Table  A,  of  the  area  of  circles. 
As  a  matter  of  fact,  the  actual  area  of  most  sizes  of 
pipe  is  a  shade  larger  than  the  area  given  for  a  circle 
of  the  stated  size.  There  is  one  notable  exception  to 
this,  and  that  is  on  the  2^2-in.  size. 

157 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

It  will  be  noticed  that  the  internal  area  of  pipes  do 
not  fully  agree  with  the  area  of  circles  as  given  in 
Table  A.  This  is  because  the  actual  internal  area  of 
steam-pipe  is  not  in  exact  accord  with  the  nominal 
area.  A  2^-in.  circle  by  Table  A  has  an  area  of 
4,908  sq.  in.,  while  a  2>^-in.  steam-pipe  by  Table  EZ 
is  found  to  have  an  area  of  a  trifle  less.  But  on  nearly 
all  sizes  the  actual  pipe-size  internally  is  a  little  larger 
than  that  given  in  Table  A.  Table  EZ  is  given  here 
because  there  often  come  places  where  it  is  of  the 
utmost  importance  to  the  fitter  to  use  the  smallest  pipe 
possible  and  hold  the  desired  velocity.  Probably  error 
in  the  use  of  2*/2-in.  pipe  is  more  general  than  on  any 
other  size,  for  the  reason  that  it  is  not  in  excess  of 
area  in  sq.  in.  as  is  the  case  with  most  other  sizes. 
Again,  the  average  fitter  seems  to  have  a  great  aver- 
sion to  reaming  the  ends,  and  when  this  is  not  attended 
to  the  area  of  the  pipe  is  considerably  decreased,  often 
to  such  an  extent  that  the  effective  area  of  the  2^2-in. 
pipe,  instead  of  being  4.784  sq.  in.,  is  found  to  be  not 
above  3^  sq.  in.,  a  deficiency  large  enough  to  upset 
completely  any  very  close  figuring  on  a  water-line 
proposition  for  instance.  What  has  been  said  in  re- 
gard to  2^in.  pipe  is  equally  true  of  all  sizes  of  pipe 
in  the  matter  of  reaming  the  end  of  pipe  to  be  used  in 
steam-fitting. 


158 


SECTION  XXI. 


Leaving  the  full  discussion  of  piping  methods  to  be 
taken  up  later,  we  are  now  ready  to  select  a  boiler 
for  our  steam-job. 

We  are  able  to  determine  how  many  B.  t.  u.  must 
be  furnished  per  hour.  The  boilers  are  all  rated  on 
a  basis  of  2-lb.  pressure  at  boiler. 

Suppose  we  have  found  we  require  500  ft.  of  radia- 
tion in  the  rooms.  Should  we  put  in  a  boiler  rated 
for  500  ft.? 

Most  assuredly  not.  Why?  In  the  first  place,  the 
piping,  covered  or  uncovered,  will  use  up  a  large  quan- 
tity of  B.  t.  u.  that  the  boiler  will  produce,  and  so, 
of  course,  those  do  not  get  to  the  radiator  at  all.  At 
the  very  lowest  estimate  this  demand  will  equal  one- 
quarter  of  the  boiler  capacity  at  2-lb.  pressure.  The 
piping  often  exceeds  on  small  jobs,  in  radiating  sur- 
face and  heat-loss  from  friction  full  40  per  cent  of 
direct  radiating  surface.  Carefully  measure  up  all 
piping,  risers,  radiator-valves  and  all  surface  connect- 
ed to  any  job  you  ever  did  with  500  ft.  or  less  direct 
radiation  and  add  to  this  the  loss  by  reason  of  fric- 
tion and  see  if  the  statement  that  25  per  cent  is 
the  very  smallest  that  can  be  allowed  for  piping,  as 
draft  on  boilers  at  2-lb.  pressure  is  not  very  conserva- 
tive. 

It  was  different  when  15  to  60-lb.  at  boiler  was  in 
vogue.  Now,  as  we  are  dealing  with  a  proposition 

159 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

mighty  close  to  hot-water  conditions  and  friction  eats 
up  a  big  percentage  of  our  available  B.  t.  u. 

Then  there  is  the  difference  in  fuel  from  year  to 
year  to  be  considered;  the  probability  that  it  will 
sometimes  be  colder  than  just  zero,  in  which  case 
more  heat  will  be  demanded;  then  again,  while  the 
boiler  is  rated  to  carry  a  certain  number  of  feet  at 
2-lb.  pressure,  how  long  at  a  time  will  it  carry  it? 
Look  catalogs  over  and  see  how  many  make  this 
apparent. 

These  boilers  may  be  rated,  for  all  you  know,  on 
a  6-hour  firing  basis,  or  more  or  less,  or  perhaps  a 
careful  measuring  up  and  testing  of  boiler  would  show 
an  8  or  even  9-hour  carrying  capacity  .for  500  sq.  ft. 
at  2-lb.  pressure.  Assume  first  an  8-hour  basis.  Then 
if  your  client  fixes  his  fire  at  9  p.  m.,  he  must  be  up 
at  5  a.  m.  next  day  to  attend  to  it,  if  the  steam  is  to 
be  supplied  at  the  time  most  needed.  Will  he  do  it? 
Hardly.  It  is  more  likely  to  be  7  a.  m.  the  next  morn- 
ing. If  so,  then  two  hours,  or  25  per  cent  of  the  rated 
value  of  the  boiler,  has  been  demanded  by  the  radia- 
tors, when  there  was  no  garantee  on  the  part  of  the 
manufacturer  to  supply  it.  The  item  of  extra  demand 
from  piping  being  25  per  cent  and  the  almost  certain 
demand  from  owner  of  a  longer  supply  than  8  hours, 
equalling,  usually,  at  least  10  hours,  or  25  per  cent 
more,  demonstrates  the  necessity  of  an  arbitrary  in- 
crease in  boiler-capacity  over  stated  amount  of  radia- 
tion required  on  job  of  at  least  50  per  cent.  A  job  re- 
quiring 5UO  sq.  ft.  of  steam-radiators  figured  on  2-lb. 
pressure  basis  should  have  at  least  a  boiler  rated  at 
750  sq.  ft.  capacity. 

As  will  be  seen,  this  is  not  because  the  boiler  is 

160 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

incorrectly  rated  but  for  reasons  entirely  outside  of 
the  special  item  of  radiators  in  the  rooms. 

Many  men  want  their  boilers  so  that  they  can  hold 
fire  12  hours  at  pressure-producing  point.  That  is 
50  per  cent  of  itself  beyond  the  rated  capacity  of 
boiler  under  selected  conditions  of  8-hour  run  and 
100  per  cent  beyond  the  rated  capacity  of  a  boiler  rated 
on  a  6-hour  firing  basis.  In  both  cases  the  additional 
tax  from  piping  and  friction  must  still  be  added. 

The  steamfitter  should  inquire  into  the  desires  of 
his  client  as  to  length  of  time  between  firing  dates  and 
figure  accordingly.  Then  he  must  know  from  the 
manufacturer  just  the  number  of  hours  the  boiler  he 
intends  to  use  will  supply  steam  at  2-lb.  pressure  and 
have  sufficient  fuel  left  in  good  condition  to  start  a 
fresh  lot  of  fuel  without  materially  diminishing  steam 
pressure. 

With  this  information  he  can  select  a  boiler  with  a 
reasonable  sense  of  security. 

Boiler  manufacturers  are  now  selling  their  product 
on  the  practical  basis  of  an  average  temperature  in 
the  radiators,  of  steam  at  212  deg.  or  less.  The  2-lb. 
pressure  is  a  factor  of  safety  against  all  sorts  of  pos- 
sible mistakes  on  the  part  of  party  installing  the 
boiler. 

It  is  up  to  the  steam-fitter  to  meet  the  present  con- 
ditions by  having  a  clear  understanding  of  the  fun- 
damental principles  governing  the  medium  he  is  at- 
tempting to  harness  and  control,  viz.,  steam. 


161 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

The  question  of  selection  of  a  boiler  for  any  house- 
heating  job  should  be  approached  by  the  steam-fitter 
without  prejudice,  and,  so  far  as  is  possible,  without 
preconceived  notions  in  favor  of  any  special  type  of 
boiler.  Because  some  job  or  jobs  have  turned  out 
well  or  badly  with  a  given  type  or  make  of  boiler  in 
use  is  no  certain  sign  that  it  will  be  the  very  best  thing 
to  put  on  the  job  in  hand,  or  that  it  should  not  receive 
proper  consideration. 

In  fact  it  may  develop  that  the  manufacturer  who 
produced  the  boiler  or  boilers  that  were  satisfactory  on 
the  previous  jobs  does  not  even  actually  make  the  best 
boiler  in  every  respect  for  the  present  condition. 

It  should  be  the  aim  of  every  steam-fitter  to  put  the 
very  best  boiler  to  procure  on  to  each  job  he  under- 
takes, and  in  order  to  do  this  he  must  candidly  con- 
sider all  the  conditions  surrounding  each  job.  He  is 
very  liable  to  find  that  the  height  of  water-line  on  one 
make  of  boiler  is  such  that  if  he  uses  that  boiler,  he  will 
be  obliged  to  use  a  size  larger  pipe  on  the  main  circuit 
than  he  would  require  if  he  used  a  boiler  of  another 
manufacturer  who  produced  a  type  with  a  lower  water- 
line.  Quite  often  the  size  of  the  smokehood  on  small- 
sized  cast-iron  boilers  becomes  a  deciding  feature.  It 
is  running  a  greater  risk  than  any  steam-fitter  can  well 
afford,  to  put  a  boiler  on  to  a  job  which  has  a  smoke- 
hood  calling  for  a  smoke-pipe  larger  than  the  face  of 
the  chimney  provided  by  the  owner.  Another  condi- 
tion which  should  have  a  very  great  influence  in  the 
decision  is  the  strength  of  the  draft.  There  is  a  very 
great  difference  in  the  various  types  of  boilers  in  this 
item  of  draft.  In  fact,  there  is  often  quite  a  differ- 
ence between  boilers  of  the  same  type  but  different 

163 


A     Practical    Manual    of    Steam    and    Hot-Water    Heating 

capacity,  as  produced  by  the  same  manufacturer.  Be- 
cause of  these  constantly  varying  conditions  it  is  up 
to  the  fitter  to  have  some  personal  knowledge  of  what 
each  type  of  boiler  will  do  under  given  conditions. 

This  does  not  mean  that  he  must  know  from  per- 
sonal experiment  what  each  boiler  manufactured  will 
do.  That  is  quite  manifestly  impossible.  If,  however, 
he  will  carefully  examine  the  cast-iron  boilers  on  the 
market  he  will  soon  discover  that  they,  in  reality,  are 
covered  by  three  distinct  types.  The  vertical  section- 
al (Fig.  13).  The  horizontal  sectional  (Fig.  14).  The 
single  casting  (Fig.  15).  Each  of  these  types  have  a 
multitude  of  variation  in  detail  of  construction  as  pro- 
duced by  the  various  manufacturers,  but  it  would  be  a 
bold  claim  to  make  that  any  type,  or  any  one  variety 
of  a  given  type,  would  always  be  the  best  choice  that 
could  be  made  for  all  conditions  that  present  them- 
selves to  the  heating  contractor. 

Only  a  very  limited  experience  in  the  installing  of 
residence-heating  plants  is  needed  to  demonstrate  that 
a  certain  make  or  type  of  cast-iron  boilers  will,  under 
apparently  similar  conditions  furnish  widely  varying 
results. 

That  two  owners,  using  the  same  size  and  type  of 
boiler  from  the  same  factory  and  installed  under  simi- 
lar conditions,  secure  different  results  is  partly  due  to 
the  difference  due  to  the  human  element  involved  is 
undoubtedly  true,  but  this  difference  in  men  is  not 
great  enough  to  account  for  the  wide  difference  in 
results  obtained. 

A  not  unusual  condition  to  find  is  that  of  the  so- 
called  twin  house  in  which  the  same  system  is  put  into 

163 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

each,  and  yet  the  results  are  measurably  different,  even 
when  cared  for  by  the  same  person. 

This  is  particularly  true  of  the  smaller  sizes  of  ver- 
tical, sectional  types.  This  is  because  of  the  greater 
effect  of  slight  differences  in  draft  upon  the  small  ver- 
tical, sectional  construction. 

For   small   jobs   the   round,   horizontal   sectional   will 


Common  Type  of  Castlron  Sectional  Poilcr. 
Fig.   13. 

generally  be  found  to  be  more  even  in  its  work  under 
similar  conditions. 

There   is,   however,   considerable     choice     in     these 
round    sectional    boilers,    especially    when    the    chimney 
draft  is  not  all  that  it  should  be.     When  the  draft  is 
known   to   be   somewhat   weak   a   round   type   with   the 
most  direct  draft  will  be  found  the  most  effective. 

164 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

On  the  other  hand,  when  the  draft  provided  for  a 
small  job  is  excessively  strong,  a  sectional  of  vertical 
construction,  with  small  ports  and  long  fire-travel,  is 
the  more  likely  to  give  satisfactory  results. 

As  a  general  thing,  it  will  be  found  that  on  jobs, 
which  require  not  to  exceed  800  sq.  ft.  of  radiation, 
that  the  most  practical  boiler  to  use  will  be  some  type 
of  the  round  horizontal  sectional  patterns.  Steam- 
boilers  of  the  round  type  with  grates  of  more  than 
30-in.  diameter  seem  to  have  rather  gone  out  of  fash- 
ion within  a  few  years,  'yet  often  it  would  be  decided- 
ly to  the  advantage  of  both  the  owner  and  the  fitter  if, 
instead  of  a  vertical  sectional,  a  large,  round  hori- 
zontal sectional  boiler  had  been  used. 

As  a  general  statement,  based  upon  an  experience 
covering  practically  the  entire  heating-territory  of  the 
United  States,  I  would  say  that  for  either  steam  or 
hot-water  heating,  jobs  requiring  less  than  1,000  sq. 
ft.  of  radiation  for  steam,  or  1,650  sq.  ft.  for  hot-water, 
the  round,  horizontal,  sectional  boiler  has  proven  itself 
to  be  more  even  in  its  performance,  and  more  eco- 
nomical, in  fuel  consumption,  than  have  the  small-sized 
vertical  sectional  types.  That  they  have  given  way  to 
the  vertical  sectional  is  a  proof  of  the  selling  ability 
of  the  manufacturers  and  I  am  inclined  to  say  of  the 
lack  of  knowledge  of  heating-surfaces  and  their  value 
on  the  part  of  the  public. 

This  statement  leads  up  to  the  discussion  of  the 
value  of  heating-surface  in  the  different  types  of  cast- 
iron  boilers. 

The  very  first  thing  to  do  is  to  emancipate  yourself 
from  all  attempts  to  measure  house-heating  boilers  by 
the  same  rules  one  would  apply  to  power-boilers. 

165 


SECTION  XXII. 


It  may  be  well  to  state  here  as  concisely  as  possible 
the  accepted  terms  of  rating  power-boilers  in  order 
to  show  how  entirely  different  the  conditions  of  rating 
really  are. 

House-heating  contractors  are  often  asked  by  those 
Who  have  not  looked  into  the  matter  at  how  many 
horse-power  a  given  cast-iron  house-heating  boiler  is 
rated. 

It  would  seem  that  this,  then,  will  be  a  good  point 
to  begin  the  explanation  of  why  the  modern  heating- 
boiler  is  not  rated  in  terms  of  power-boilers  or  by 
horse-power. 

"The  term  horse-power  has  two  meanings  when  ap-> 
plied  by  engineers :  First,  an  absolute  unit  or  measure 
of  the  rate  of  work  done  in  a  given  period  of  time." 

This  unit  of  time  has  been  accepted  as  one  minute ; 
and  the  measure  of  work  has  been  accepted  as  that 
necessary  to  raise  33,000  Ib.  one  foot,  or  33,000  foot-lb. 

"When  the  work  done,  the  conversion  of  water  into 
steam,  cannot  be  expressed  in  foot-pounds  of  avail- 
able energy,  the  usual  value  given  to  the  term  horse- 
power is  the  evaporation  of  30  Ib.  of  water  having  a 
temperature  of  100  deg.  F.  into  steam  at  70-lb.  pressure 
above  the  atmosphere." 

The  term  horse-power  was  first  used  by  James  Watt 
as  a  means  of  comparison.  He  concluded  that  a  good 
London  draught-horse  could  exert  sufficient  energy  or 
power  to  raise  33,000  Ib.  one  foot  above  the  ground  in 

166 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

one  minute  and  he  therefore  decided  that,  if  the  energy 
or  power  exerted  by  such  a  horse  was  equalled  by  the 
energy  or  power  developed  by  steam  evaporated  from 
30  Ib.  of  water  at  some  stated  pressure,  that  energy 
should  be  termed  a  horse-power.  It  will  be  seen  that 
the  unit  of  time  and  the  unit  of  energy  to  be  exerted  in 


Fig.   14. 

the  unit  of  time  are  simply  terms  of  comparison  which 
have  been  accepted  by  common  consent  as  a  guide  or 
measure. 

"The  second  definition  of  the  term  horse-power  is  an 
approximate  measure  of  the  size,  capacity,  value  or  rat- 
ing of  a  boiler,  engine,  water-wheel  or  other  source  or 
conveyor  of  energy,  by  which  measure  it  can  be  de- 

167 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

scribed,  bought,  sold,  advertised  and  so  forth.  No 
definite  value  can  be  given  to  this  measure,  which 
varies  largely  with  local  custom  or  individual  opinion 
of  the  makers  and  users  of  machinery.  The  nearest 
approach  to  uniformity  which  can  be  arrived  at  in  the 
term  horse-power  used  in  this  sense,  is  to  say  that  a 


DM0 


Common  Types  of  Coot  -Iron 
Castmq  0o//crJ. 

Fig.  15. 


boiler,  engine,  water-wheel,  or  other  machine,  rated  at  a 
certain  horse-power,  should  be  capable  of  steadily  de- 
veloping that  horse-power  for  a  long  period  of  time 
under  ordinary  conditions  of  use  and  practice,  leaving 
to  local  custom,  to  the  judgment  of  the  buyer 
or  seller,  to  written  contracts  of  purchase  and  sale,  or 


ins 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

to  legal  decisions  upon  each  contract,  the  interpretation 
of  what  is  meant  by  the  term  "ordinary  conditions  of  use 
and  practice."  (Trans.  A.  S.  M.  E.,  Vol.  7,  page  226.) 

When  the  Centennial  Exhibition  was  held,  the  question 
of  testing  power-boilers  was  very  carefully  considered 
and  the  judges  concluded  to  define  a  horse-power  for 
commercial  tests  to  be  the  evaporation  of  30  Ib.  of  water 
per  hr.  from  feed-water  of  100  deg.  temperature  F.  into 
steam  at  70-lb.  pressure  per  sq.  in.  above  atmosphere. 
These  conditions  were  considered  as  representing  fairly 
the  practice  in  this  country  of  the  users  of  power- 
boilers. 

It  will  be  observed  that  this  calls  for  the  use  of  1110.2 
B.  t.  u.  to  evaporate  one  pound  water. 

The  unit  of  power  proposed  for  this  country  therefore 
is  the  development  of  33,305  heat  units  per  hour.  This 
unit  has  been  accepted  by  the  engineering  societies  of 
the  country  as  the  proper  base  of  comparison  for 
power-boilers. 

In  order  to  clearly  understand  the  very  considerable 
difference  in  the  manner  of  rating  we  must  explain  the 
unit  of  evaporation  as  it  is  called.  Professor  W.  Kent  de- 
fines it  as  follows :  "It  is  the  custom  to  reduce  results 
of  boiler-tests  to  the  common  standard  of  weight  of  water 
evaporated  by  the  unit  weight  of  the  combustible  por- 
tion of  the  fuel,  the  evaporation  being  considered  to 
have  taken  place  at  mean  atmospheric  pressure,  and  at 
the  temperature  due  to  that  pressure,  the  feed-water 
being  also  assumed  to  have  been  supplied  at  that  tem- 
perature. This  is,  in  technical  language,  said  to  be  the 
equivalent  evaporation  from  and  at  the  boiling  point 
at  atmospheric  pressure,  or  "from  and  at  212  deg.  F." 

This  unit  of  evaporation  as  described  by  Prof.  Kent  is 

169 


A     Practical    Manual    of    Steam    and    Hot-Water    Heating 

equivalent  to  the  development  of  965.7  B.  t.  u.  or  as  com- 
monly stated  966  B.  t.  u.  The  measure  for  comparing 
the  "duty  of  power-boilers"  is  the  number  of  pounds  of 
water  evaporated  per  pound  of  combustible,  the  evapora- 


65  f  of  Heat  Value  of  Fuel 


of  Heat  Va/ue  0f 


/ 


Dunng  Com  bust/ on. 


Fig.   16. 

tion  being  reduced  to  the  standard  of  "from  and  at  212 
deg.  F. ;  that  is,  it  is  the  equivalent  evaporation  from 
water  at  a  temperature  of  212  deg.  F.  into  steam  of  the 
same  temperature. 

170 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 


measure  of  the  capacity  of  a  power-boiler  is  the 
amount  of  boiler-horse-power  developed,  a  horse-power 
being  defined  as  the  evaporation  of  30  Ib.  of  water  per 
hour  from  100  deg.  F.  into  steam  at  70-lb.  pressure  or 
3^2  Ib.  per  hour  from  and  at  212  deg.  F." 

The  measure  of  relative  rapidity  of  steaming  of  power- 
boilers  is  the  number  of  pounds  of  water  evaporated  per 
hour  per  square  foot  of  heating-surface.  The  measure  of 
relative  rapidity  of  combustion  of  fuel  in  power-boiler- 
furnaces  is  the  number  of  pounds  of  coal  burned  per  hour 
per  square  foot  of  grate-surface.  (Kent,  page  678.) 

These  extracts  from  the  highest  American  authorities 
as  to  what  constitutes  a  horse-power,  in  a  ppwer-boiler 
value,  is  ample  to  show  the  futility  of  attempting  to  apply 
"horse-power"  data  to  the  present  ratings  of  cast-iron 
steam-boilers. 

The  power-boiler  begins  to  rate  for  horse-power  when 
the  steam  has  a  gage  pressure  of  70  Ib.  The  maximum 
rating  of  the  cast-iron,  house-heating  boiler  is  only  2 
Ib.  at  the  boiler.  The  power-boiler  is  to  evaporate  30  Ib. 
of  water  into  steam  of  316  deg.  F.  temperature  in  one 
hour,  in  order  to  develop  one  unit  or  one  horse-power, 
while  the  cast-iron,  house-heating  boiler  is  rated  to 
evaporate  approximately  34^4  Ib.  of  water  into  steam  of 
212  F.  in  same  time. 

The  power-boiler  is  supposed  to  deliver  its  steam  to  an 
engine  where  a  portion  of  its  heat  and  power  is  used  by 
the  engine  and  a  much  larger  portion  in  the  shape  of 
latent  heat  is  thrown  off  in  the  exhaust.  This  exhaust 
represents  a  great  fuel  consumption,  how  great  can  be 
easily  considered  when  we  consider  the  fact  that  the 
exhaust  from  an  ordinary  electric-light  plant  is  usually 
sufficient  to  heat  the  houses  lighted.  The  house-heat- 

171 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

ing  boiler  is  supposed  to  use  all  the  steam  produced 
in  it  for  the  sole  purpose  of  heating. 

Figure  16  will  give  an  idea  of  this  fuel-consumption 
loss  when  the  exhaust  steam  from  a  power-boiler  is  not 
untilized  in  heating  and  also  shows  very  clearly  why 
boilers  which  are  to  be  used  exclusively  for  heating  are 
not  rated  in  terms  used  to  describe  power-boilers. 

Almost  without  exception,  persons  who  are  accustomed 
to  high-pressure  boilers  seem  to  think  they  must  deter- 
mine low-pressure  house-heating  plants  by  high-pres- 
sure terms  and  conditions.  They  forget,  or  perhaps  do 
not  know,  that  the  horse-power  unit  has  a  temperature  of 
316  deg.,  while  the  house^boiler  unit  has  a  temperature 
of  only  212  deg.  F. 

Almost  never  does  a  client  who  is  acquainted  with 
high-pressure  work  fail  to  ask  the  dealer  in  house-heat- 
ing boilers  what  horsepower  the  boiler  under  discussion 
will  develop.  If  the  dealer  or  steam-fitter  answers  that 
he  does  not  know,  in  nine  cases  out  of  ten,  he  loses  the 
prospective  customer.  Or,  if  the  dealer  states  that  house- 
heating  boilers  are  sold  on  an  evaporation  basis,  not  on 
horse-power  ratings,  the  customer  immediately  states 
that  there  is  no  difference,  and  wants  to  know  what 
the  size  of  the  grate  is  in  the  boiler  under  consideration. 

Some  patience  on  the  part  of  the  dealer  is  usually 
called  for  at  this  stage  of  the  negotiations,  especially 
if,  as  is  often  the  case,  the  dealer  is  not  expert  in  power- 
work. 


172 


SECTION  XXIII. 


I  am  taking  up  this  side  of  the  boiler  question  at  this 
point  because  it  has  so  often  come  to  my  knowledge 
that  the  sale  of  a  really  proper  house-heating  boiler  has 
been  lost  to  some  steamfitter  on  small  house-work, 
because  he  could  not  translate  into  power-terms  the 
cast-iron,  heating-boiler  ratings. 

The  man  who  immediately  wants  to  know  the  horse- 
power of  a  modern  house-heating  boiler  is  usually  a  very 
intelligent  person,  one  who  can  be  shown,  and  who  is 
capable  of  understanding  any  clear  explanation.  But  he 
is  also,  usually,  one  who  has  a  lot  of  ideas  perfectly 
applicable  to  power-work  with  a  working  pressure  of 
anywhere  from  30  to  100  Ib.  pressure  per  sq.  in.  These 
ideas  must  be  translated  into  the  modern  practice  of 
heating  with  the  boiler  pressure  not  above  2  Ib.  and  the 
maintenance  of  that  pressure  for  8  or  10  hours  or  even 
12  hours  on  one  firing. 

In  the  process  of  this  translation  many  things,  of 
course,  are  sure  to  arise  that  can  not  be  taken  up  in  de- 
tail here,  but  the  more  frequent  things  concern  only  a  few 
points.  The  careful  reader  of  these  pages  will  probably 
be  able  to  fully  explain  most  any  question  that  will  come 
up.  The  matter  of  grate-surface,  fire-surface,  ratio  of 
heating  to  grate-surface,  heating-surface  per  horse- 
power, pounds  of  water  evaporated  per  square  foot  of 
heating-surface,  pounds  of  fuel  per  square  foot  of  grate 
per  hour — all  these  are  questions  almost  sure  to  be 
asked  and  if  answered  without  carefully  explaining  the 

173 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

different  view  the  house-heating  man  takes  of  the 
value  of  each  from  that  taken  by  the  power-man,  the 
steam-fitter  is  pretty  certain  to  have  some  rather  sar- 
castic remarks  addressed  to  him. 

All  these  questions  are  important  and  are  all  proper 
ones  to  ask,  the  difficulty  with  them  being  that  they  have 
a  somewhat  different  aspect  when  applied  to  house-heat- 
ing boilers  than  when  applied  to  the  power-boilers.  Read- 
ers will,  of  course,  understand  that  the  foregoing  re- 
marks are  supposed  to  apply  to  small  house-heating  boil- 
ers only.  In  jobs  of  sufficient  size  to  require  power-boil- 
ers for  mechanical  purposes,  the  exhaust  would  be  prob- 
ably utilized  and  in  selecting  such  a  boiler  the  conditions 
necessary  to  produce  the  most  economy  in  power  would 
be  sought,  in  the  same  manner  that  in  a  small  job  where 
the  boiler  is  to  be  used  for  heating  only,  conditions  should 
be  sought  that  will  give  the  most  economy  in  heat. 

High-pressure  engineers  quite  frequently  use  data  ap- 
proximately as  follows : 

1  sq.  ft.  of  heating-surface  will  evaporate  2  Ib.  water 
per  hr. 

1  horse-power  equals  30  Ib.  water  evaporated. 

15  sq.  ft.  of  heating-surface  equals  1  horse-power. 

1  horse-power  will  supply  100  sq.  ft.  of  radiation. 

1  sq.  ft.  of  heating  surface  will  supply  7  sq.  ft.  of 
radiation. 

1  sq.  ft.  of  radiation  will  condense  .03  Ib.  steam  per  hr. 

It  will  be  at  once  evident  that  these  conditions  cannot 
apply  to  a  boiler  which  is  rated  at  its  maximum  at  2  Ib. 
The  average  cast-iron  steam  boiler  for  heating  purposes 
under  average  working  conditions  will  evaporate  from 
2  to  6  Ib.  of  water  per  hr.  per  sq.  ft.  of  heating  surface. 
Possibly  a  grand  total  average  of  all  the  boilers  now  in 

174 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

use  would  be  below  rather  than  over  4  Ib.  per  hour.  Then, 
as  has  been  shown,  34.5  Ib.  of  water  evaporated  from  and 
at  212  deg.  F.  equal  1  horse-power.  The  common  use 
of  3-column  radiators  on  all  house-heating  jobs  create  an 
entirely  new  condition  from  which  to  figure  the  condensa- 
tion per  hour,  and  it  is  only  under  most  exceptional  con- 
ditions that  the  condensation  from  these  .radiators  will 
reach  even  that  from  0.25  Ib.  of  steam  per  hour.  But 
as  something  must  be  taken  as  a  basis  upon  which  to 
work  from,  the  manufacturers  seem  to  have  tacitly  accept- 
ed 0.25  Ib.  of  steam  condensed  as  expressing  the  con- 
densing power  of  cast-iron  radiators  per  sq.  ft.  per  hour 
when  considering  the  evaporative  power  of  cast-iron  boil- 
ers. Under  these  conditions,  altogether  different  results 
will  be  obtained  from  those  which  the  high-pressure  data 
would  produce.  The  statement  of  present  ratings  for 
cast-iron  heating-boilers  could  be  fairly  presented,  per- 
haps, by  data  something  like  the  following: 

1st.  34.5  Ib.  of  water  evaporated  from  and  at  212  deg. 
F.  equals  1  horse-power. 

2nd.  One  square  foot  of  heating  surface  in  the  ordi- 
nary cast-iron  heating  boiler  will  evaporate  from  2  to 
6  Ib.  of  water  per  hour,  from  and  at  212  deg.  F. 

3rd.  One  square  foot  of  cast-iron  radiation  will  con- 
dense from  1/5  to  ^  Ib.  of  steam  per  hour  in  air  of  70 
deg.  with  pressure  at  the  boiler  at  2  Ib. 

From  the  foregoing  it  is  evident  that  the  condensation 
of  the  radiators  per  hour,  per  square  foot  of  surface, 
practically  determines  the  so-called  horse-power  capacity 
of  the  boiler  to  which  it  is  attached.  It  is  also  evident 
that  the  heating  surface  of  the  boiler  itself  cannot  be 
taken  as  a  certain  guide  to  its  capacity  to  carry  a  given 
number  of  feet  of  radiation. 

175 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

The  old  notion  that  1  horse-power  would  only  carry 
100  sq.  ft.  of  radiation  falls  to  the  ground  badly  crip- 
pled in  the  examination. 

The  high-pressure  100-ft.  notion  is  developed  in  this 
way.  With  70-lb.  pressure  at  boiler  the  evaporation  of  30 
Ib.  of  water  equals  1  horse-power.  At  this  difference  of 
temperature  between  the  steam  and  70  deg.  F.  in  the  room 
0.3  Ib.  of  steam  will  be  condensed  per  hour  per  square 
foot  of  surface  in  the  radiator.  Then  the  30  Ib.  steam  di- 
vided by  the  0.3  Ib.  which  1  sq.  ft.  condenses  equals  the 
100  sq.  ft.  required  to  evaporate  the  30  Ib.  steam  at  70-lb. 
pressure  at  boiler. 

It  has  been  shown  that  with  2  Ib.  at  boiler  there  must 
be  condensed  34.5  Ib.  of  water  to  equal  1  horse-power ; 
that  the  30  Ib.  of  water  evaporated  for  a  horse-power  is  at 
the  temperature  of  steam  at  70-lb.  pressure,  while  the 
34.5  Ib.  must  be  evaporated  into  steam  at  a  lower 
temperature  by  about  100  deg.  F.  If  the  condensation 
per  hour  per  square  foot  of  radiation  is  only  1/5  Ib., 
then  with  a  condensation  of  34.5  Ib.  per  hour,  the  boiler 
would  supply  a  heating  surface  of  172.5  sq.  ft.  per  horse- 
power. Thus  34.5  divided  by  1/5  equals  172.5  to  be 
placed  in  the  rooms.  If  the  radiators  were  so  efficient 
that  they  condensed  1/3  Ib.  of  steam  per  sq.  ft.  per  hour, 
then  1  horse-power  would  only  require  103.5  sq.  ft.  of 
radiation  per  horse-power. 

The  following  table  FZ  will  show  very  clearly  the 
varying  amounts  of  radiation  that  one  so-called  horse- 
power will  "carry"  at  different  rates  of  condensation : 

If  any  reader  should  ever  find  radiators  so  excellent 
that  they  will  condense  more  than  1/3  Ib.  of  steam  per 
hour,  or  be  so  unfortunate  as  to  purchase  some  that  will 
condense  less  than  1/5  Ib.  per  hour  (there  have  been 

176 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

such  in  the  market)  he  can  get  the  number  of  square  feet 
of  surface  that  will  be  required  to  equal  1  horse-power  by 
finding  the  evaporation  per  square  foot  per  hour  and 
divide  the  34.5  Ib.  steam  required  for  1  horse-power  by 
the  ascertained  evaporation.  Thus ;  Suppose  that  some 
one  has  produced  a  radiator  that  will  condense  ^  Ib. 
steam  per  square  foot  per  hour :  34.5  divided  by  M>  equals 
69  sq.  ft.  that  1  horse-power  would  "carry."  Or,  assume 
that  the  radiator  was  so  poor  that  it  would  not  condense 
more  than  1/6  Ib.  per  sq.  ft.  per  hour :  then  34.5  divided 
by  1/6  equals  207  sq.  ft.  radiator  surface  required  to 
condense  1  horse-power  in  1  hour. 

As  previously  stated,  the  boiler  manufacturers  have 
practically  accepted  as  the  basis  for  rating  their  boilers 
a  condensing  power  of  y\  Ib.  of  steam  per  hour  per  sq. 
ft.  of  radiation. 

By  taking  this  as  the  rule  to  apply  to  all  cast-iron  heat- 
ing boilers,  quite  a  few  of  the  talking  points  of  the 
average  boiler  salesman  can  be  compared  and  checked 
against  his  catalog. 

The  first  point  to  ascertain  is  the  evaporative  power  of 
the  boiler  under  consideration  per  square  foot  of  its 
heating  surface.  The  salesman  may  claim  that  the  boiler 
he  is  trying  to  sell  has  an  evaporating  power  of  6  to  8 
Ib.  of  water  per  hour,  per  square  foot  of  the  heating  sur- 
face in  the  boiler. 

You  desire  a  small  boiler  of  say,  500  sq.  ft.  rated  capac- 
ity. You  recall  that  the  rating  of  all  cast-iron  steam 
boilers  is  on  the  basis  of  y\  Ib.  steam  per  sq.  ft. ;  then  the 
500-lb.  boiler  you  require  must  deliver  125  Ib.  steam  per 
hour.  If  this  boiler  can  evaporate  8  Ib.  water  per  square 
foot  of  heating  surface  then  the  boiler  can  only  have  15.6 
sq.  ft.  of  heating  surface.  (125  -=-  8  =  :  15.6)  If  the 

177 


A     Practical    Manual    of    Steam    and    Hot-Water    Heating 


sales  agent  is  correct,  then  it  must  be  necessary  to  drive 
the  fire  at  a  very  high  temperature.  Only  a  few  of 
the  catalogs  publish  the  producer's  claim  as  to  square 
feet  of  heating  surface  in  his  goods,  and  none  of  them 
as  yet  state  the  number  of  hours  that  the  rating  they  do 


Pounds   of  Water 

TABLE  FZ. 

Sq.     Ft.     Heating 

Sq.  Ft.  of  Radiat- 

Evaporated   per 

Surface    in    the 

ors   'Condensing 

Sq.  Ft.   Heating 

Boiler  to  1  H.  P. 

1/5  Ib.  Steam  to 

Surface  per  Hr. 

1    sq.    ft.    Boiler 

Surface. 

2 

17.25 

10.00 

%1A 

13.80 

12.50 

3 

11.50 

15.00 

y/2 

9.85 

17.50 

4 

8.625 

20.00 

V/2 

7.66 

22.50 

5 

6.90 

25.00 

5^ 

6.275 

27.50 

6 

5.75 

30.00 

give  can  be  sustained.  Among  the  few  published  claims 
for  fire  surface  in  boilers  rated  for  500  sq.  ft.  steam,  I 
find  the  range  to  be  from  24:%  to  84  sq.  ft.  Or  from  5.15 
Ib.  to  l^  Ib.  of  water  condensed  per  sq.  ft.  heating  surface 
per  hour,  but  T  find  no  catalog  which  states  the  stack- 
temperature  that  was  maintained  when  the  rating  was 
fixed,  or  the  pounds  of  fuel  burned  per  hour  during  the 
test.  Yet  these  are  all  things  of  importance  that  the  pur- 
chaser is  entitled  to  know :  things  of  the  utmost  import- 
ance to  the  steam-fitter  who  has  to  garantee  the  working 
of  the  job,  and  the  heat  that  it  will  produce.  If  the  chim- 
ney to  which  the  boiler  is  to  be  attached  has  not  sufficient 
draft  to  maintain  a  stack-temperature  of  600  deg.  it  would 
be  useless  to  put  on  that  job  a  boiler  that  must  develop 

178 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

that  stack-temperature  in  order  to  maintain  its  rating. 

The  boiler  may  be,  and  probably  is,  correctly  rated. 
In  fact  it  may  have  developed  a  power  considerably  in 
excess  of  the  catalog-rating  under  the  600-deg.  stack-tem- 
perature. 

TABLE  FZ. 

Sq.  Ft.  of  Radiat-     Sq.  Ft.  of  Radiat-    Sq.    Ft.    Boiler    Will 
ors    Condensing        ors    Condensing  "Carry"  per 


54  lb.  to  1  sq.  ft. 

1/3  lb.  to  1  sq. 

H.  P. 

Boiler  Surface. 

ft.  Boiler  Surface. 

Lb. 

Lb. 

Lb. 

1/5 

1/4 

1/3 

8 

6.00 

172 

138 

103 

10 

7.50 

172 

138 

103 

12 

9.00 

172 

138 

103 

14 

10.50 

172 

138 

103 

16 

12.00 

172 

138 

103 

18 

13.50 

172 

138 

103 

20 

15.00 

172 

138 

103 

22 

16.50 

172 

138 

103 

24 

18.00 

172 

138 

103 

But  this  same  boiler,  working  at  a  stack-temperature  of 
350  deg.  may  not,  probably  will  not,  develop  a  power  to 
evaporate  more  water  than  will  supply  375  sq.  ft.  of 
radiation  with  steam. 

The  highest  authorities  obtainable  all  agree  that  the 
point  of  greatest  fuel-economy  in  power-boiler  construc- 
tion is  that  which  is  so  constructed  that  each,  square  foot 
of  heating  surface  will  develop  from  2  to  4  lb.  of  steam 
per  square  foot  of  heating  surface  per  hour  with  a  stack- 
temperature  from  450  to  500  deg.  F.  in  the  stack-gases. 
As  has  been  demonstrated,  the  house-heating  boiler  works 
under  a  much  lower  pressure  and  has  to  evaporate  34.5 
lb.  of  water  per  hour  at  2-lb.  pressure  at  the  boiler  in- 
stead of  30  lb.  at  70  lb.  pressure  as  does  the  power-boiler. 

179 


SECTION  XXIV. 


This  difference,  coupled  with  the  long  interval  between 
firing  dates,  has  developed  the  fact  that  for  house-heating 
boilers  a  stack-temperature  of  from  300  to  450  deg.  F. 
is  within  the  range  of  reasonable  requirement  for  either 
the  producer  or  the  owner.  If,  however,  the  firing  period 
is  to  be  extended  to  12  hours,  or  from  6  to  7  at  night, 
to  6  or  7  in  the  morning,  then  a  constant  stack-tempera- 
ture of  450  deg.  would  be  found  to  be  high  for  practical 
use. 

Owing  to  the  fact  that  the  catalogs  of  nearly  every 
cast-iron  heating  boiler  manufacturer  fail  to  give  anything 
in  the  way  of  definite  information  regarding  the  fire  sur- 
face, the  stack-temperature  required  to  secure  the  evap- 
oration claimed  per  square  foot  of  heating  surface,  the 
total  evaporative  capacity  secured  when  the  tests  were 
made,  the  pounds  of  coal  that  the  fire-pot  holds,  when 
what  is  considered  by  the  manufacturer  as  the  proper 
amount  for  a  full  charge  is  to  be  put  in,  or  the  pounds  of 
coal  burned  per  hour  during  the  test,  there  is  but  little, 
apparently,  that  the  steam-fitter  or  owner  has  to  guide 
him  in  selecting  a  boiler. 

About  all  that  the  average  catalog  of  heating  boilers 
gives  out,  that  can  be  easily  made  available  for  the  pur- 
pose of  determining  whether  a  given  boiler  is  in  reality  a 
suitable  one  to  put  on  a  certain  job  or  not,  is  the  grate 
size,  the  height  of  water-line,  diameter  of  smoke-pipe, 
total  height  and  width,  and  the  claimed  radiation-capac- 
ity, or  rating.  Each  and  every  manufacturer  will  claim 

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A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

that  his  goods  are  "conservatively"  rated.  "That  the 
rating  is  based  on  the  assumption  that  hard  coal  is  to 
be  used  for  fuel/'  "that  the  steam  ratings  are  based  on  a 
standard  of  two  (2)  pounds  pressure  at  the  boiler,  and 
the  water-ratings  at  a  temperature  of  180  deg.  F.  as  it 
leaves  the  boiler." 

It  has  been  said  by  one  writer  that  the  manner  of  figur- 
ing for  radiating  surface  under  the  old  ratio-rules  might 
be  called  "rules  of  thumb."  We  have  seen  that  the  usual 
manner  of  fixing  pipe-sizes  is  a  guessing  contest.  What 
can  be  said  of  the  way  the  boiler  ratings  are  stated? 

No  man  is  warranted  in  saying  the  rating  on  any  house- 
heating  boiler  is  not  correct.  There  is  not  a  boiler  rating 
published  that  is  not  a  conservative  rating  at  some  stack 
temperature,  and  yielding  a  certain  amount  of  condensa- 
tion per  square  foot  of  grate  and  heating  surface  per 
hour.  The  fact  is  that,  if  all  the  ratings  were  brought  to 
one  common  basis  there  would  be  many  surprises  among 
the  fitters  of  this  country. 

It  is  not  an  unheard-of  thing  that  the  castings  made 
from  one  set  of  boiler  patterns  are  assembled  and  sold 
under  different  names,  and  that  the  rating  given  under 
each  name  is  different  from  that  of  the  same  castings 
under  another  name. 

The  selling  agent  who  is  disposing  of  each  product  is 
willing  to  garantee  that  the  rating  on  his  particular 
name  of  boiler  is  very  conservative  and  based  on  2-lb. 
pressure  at  boiler.  He  is  perfectly  willing  to  go  farther 
and  garantee  that  the  boiler  will  "hold  its  rating  provid- 
ing it  is  fired  with  suitable  fuel  and  given  sufficient 
draft."  But  not  one  of  them  states  the  time  in  hours  that 
he  expects  his  particular  boiler  to  "carry"  its  load. 

Like  many  of  the  apparent  puzzles  in  the  heating  bus- 

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A     Practical    Manual    of    Steam    and    Hot-Water    Heating 

iness,  the  solution  is  simple  when  the  full  facts  are 
known. 

Bearing  in  mind  that  at  this  time  the  most  of  the 
catalogs  are  giving  out  but  little,  if  any,  information  in 
regard  to  ratings,  it  may  be  of  interest  to  study  this  steam 
boiler-rating  question  from  just  the  available  data  given 
out  with  most  of  the  ratings,  aided  by  the  almost  un- 
questioned fact  that  the  average  condensation  of  water 
per  pound  of  anthracite  coal  is  8^  Ib. 

The  first  thing  to  find  out  is  whether  the  total  capacity 
of  a  given  boiler  to  evaporate  water  is  practically  con- 
stant at  all  stack-temperatures. 

For  the  purpose  of  this  illustration  let  us  take  a  steam- 
boiler  having  a  catalog  rating  of  500  sq.  ft.  The  grate 
size  may  be  given  as  432  sq.  in.  or  3  sq.  ft.  The  catalog 
does  not  usually  give  anything  definite  as  to  size  of  the 
fire-pot,  or  the  amount  of  coal  in  pounds  considered  as 
a  full  charge,  therefore  we  must  get  at  it  approximately. 

The  catalog  most  certainly  will  not  state,  as  it  should, 
the  number  of  pounds  of  coal  burned  per  hour  per  square 
foot  of  grate  surface  when  the  rate  was  fixed.  Nor  will 
it  state,  as  it  should,  the  pounds  of  hard  coal  considered 
by  the  manufacturer  as  being  the  fire-pot  capacity. 

A  catalog,  giving  the  stack-temperature  during  the 
test,  or  the  number  of  hours  the  boiler  is  supposed  to  run 
on  one  charge  of  fuel  and  maintain  its  rating,  has  not 
as  yet  been  published,  so  far  as  I  have  knowledge  of 
catalogs. 

Each  of  these  things  must  be  made  clear,  however,  if 
boiler- ratings  are  to  be  of  any  more  value  to  the  steam- 
fitter  than  that  of  a  guide  to  a  blind  guess  as  to  what  the 
"garanteed  rating"  may  possibly  mean. 

If  the  reader  will  follow  closely  at  this  time  he  will 

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A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

find  the  reasons,  or  at  least  some  of  them,  why  all  of 
these  things  should  appear  in  the  description  of  every 
boiler  as  surely  as  the  height  of  the  water  line,  or  any 
item  the  producers  now  give  out.  Having  only  the  grate 
surface  to  start  with,  but  with  every  desire  to  be  per- 
fectly fair  to  the  manufacturer,  let  us  find  out,  if  we  can, 
what  this  500-ft.  rating  may  mean. 

Probably  no  one  producer  would  object  to  having  his 
boiler  figured  as  burning  8  Ib.  coal  per  hour,  per  square 
foot  of  grate  as  the  base  of  getting  at  the  full  capacity 
of  it.  His  catalog  says  the  grate  in  this  boiler  has  3  sq. 
ft.  of  surface.  Then  the  boiler,  when  "sufficient  draft 
and  good  hard  coal  is  used,"  will  burn  24  Ib.  coal  per 
hour  during  the  test.  As  there  is  absolutely  no  way  of 
finding  out  positively  the  square  feet  of  heating  or  fire 
surface  from  the  modern  catalogs,  with  two  or  three 
notable  exceptions,  let  us  assume  that  this  boiler  has 
the  average  heating  surface  shown  to  be  in  these,  namely, 
54  sq.  ft.  In  order  to  find  out  the  full  evaporative  power 
of  the  boiler  it  is  evident  that  we  must  first  find  the 
pounds  of  coal  that  the  grate  will  burn  per  hour,  and 
multiply  that  amount  by  the  pounds  of  water  that  the 
coal  will  evaporate.  The  catalog  fails  to  state  the  evapor- 
ative value  of  the  coal  used  at  time  boiler  was  rated, 
therefore  we  will  use  the  average  evaporative  power  of 
%l/2  Ib.  of  water  to  the  pound  of  coal. 

Twenty-four  pounds  of  coal  then  yields  204  Ib.  of 
steam.  The  54  sq.  ft.  heating  surface  has  an  evaporative 
value  of  3.78  Ib.  per  ft.  per  pound  of  coal  burned.  To 
get  the  full  value  of  the  boiler,  multiply  the  total  heating 
surface  by  the  value  of  one  foot  of  it  (54  X  3.78  =  204 
Ib.)  and  divide  that  sum  by  the  total  pounds  of  coal  the 
boiler  will  consume  in  one  hour,  or  24  Ib.  The  full 

183 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

evaporative  power  of  the  boiler  then  is  8.5  Ib.  steam  for 
each  pound  of  coal  when  24  Ib.  are  consumed  in  one 
hour.  But  suppose  a  slower  combustion,  a  lower  stack- 
temperature,  causing  only  20  Ib.  of  coal  to  be  burned  per 
hour.  The  showing  as  to  total  boiler  capacity  will  not  be 
materially  changed,  for  each  pound  of  coal  yields  Sy2  Ib. 
evaporation  whether  it  is  burned  with  a  stack-tempera- 
ture of  700  deg.  or  at  300  deg.  It  is  not  at  this  point 
that  the  stack-temperature  becomes  vital.  But  to  clear 
the  point  as  to  the  total  evaporative  power  of  the  boiler 
under  consideration.  The  20  Ib.  of  coal  will  evaporate 
20  X  8y2  =  170  Ib.  water  per  hour.  170  -f-  54  =  3.15  Ib. 
per  square  foot  of  heating  surface  or  a  full  value  of  8.5  Ib. 
(54  X  3.15  =  170  +  20  =  8.5).  At  a  still  slower  com- 
bustion, say,  4  Ib.  per  square  foot  of  grate  per  hour,  the 
full  value  of  the  heating  power  remains  practically  the 
same.  The  12  Ib.  coal  burned  yield  102  Ib.  evaporation ; 
the  heating  surface  is  worth  only  1.9  per  foot  or  a  full 
value  of  102  Ib.  per  hour.  This,  divided  by  the  total 
coal  burned,  or  12  Ib.,  shows  the  full  power  of  the  boiler 
to  be  the  same  as  in  the  previous  cases  mentioned,  or 
8.5  Ib. 

This  shows  that  the  rate  of  combustion,  within  reason- 
able limits,  does  not  affect  the  total  evaporating  power  of 
the  boiler. 

What,  then,  is  the  use  of  the  stack-temperature  at  time 
of  rating  being  in  the  catalog?  If  the  rating-question 
stopped  at  the  point  of  finding  the  total  capacity  of  a 
boiler  to  condense  water,  there  would  be  no  need  of  it, 
but,  as  we  shall  see,  the  whole  rating-question  does  not 
end  with  the  finding  out  the  size  of  grate,  the  square  feet 
of  heating  surface,  and  the  pounds  of  coal  burned  per 
hour  per  square  foot  of  grate. 

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A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

It  is  very  needful  that  the  engineer,  or  the  steam-fitter, 
shall  know  how  many  hours  the  boiler  will  continue  to 
convert  water  into  steam  on  one  full  load  of  coal.  He 
must  know  as  to  the  rate  of  combustion  required,  in  order 
to  determine  whether  the  chimney  provided  by  the  owner 
is  capable  of  furnishing  the  required  stack-temperature, 
and  he  needs  to  know  how  many  pounds  of  coal  the  fire- 
pot  will  hold,  in  order  that  he  may  intelligently  use  the 
boiler  under  conditions  that  vary  from  those  selected 
by  the  manufacturer  in  rating  the  boiler. 

Having  found  that  the  boiler  has  a  possible  power  of 
condensing  8.5  lb.  water  per  sq.  ft.  of  heating  surface 
per  hour,  and  that  there  are  54  sq.  ft.  in  the  boiler,  the 
information  is  of  no  particular  value  unless  the  pounds 
of  coal  the  fire-pot  will  contain  is  also  known. 

It  is  certain  that  if  24  lb.  of  coal  are  needed  to  carry 
the  rating  one  hour,  it  will  require  eight  times  as  much 
to  continue  the  work  for  eight  hours.  But  where  is  the 
boiler  catalog  that  plainly  states  the  capacity  of  the  fire- 
pot  in  pounds  of  coal  of  any  boiler  listed  ? 

In  the  case  we  are  considering,  the  fire-pot  should  hold 
not  less  than  240  lb.  as  a  full  charge,  for  an  8-hr,  run  at 
full  capacity  would  use  192  lb.  and  no  boiler  should  burn 
up  over  4-5  of  its  total  fire-pot  capacity  during  the  time 
it  is  to  keep  up  steam  without  new  fuel  being  added.  At 
least  1-5  of  the  coal  will  be  needed  to  start  the  new 
fuel-charge  into  combustion. 

We  will  therefore  consider  that  there  are  192  lb.  of  hard 
coal  to  be  used  in  making  the  tests  and  that  the  test  is 
to  be  made  for  6  different  stack-temperatures,  or  rates 
of  combustion,  from  750  deg.  F.  to  250  deg.  F.,  inclusive. 

The  data  we  have  accumulated  in  regard  to  this  boiler 
can  now  be  tabulated  as  follows : 

185 


A    Practical    Manual    of    Steam    and    Hot- Water    Heating 

Size  of  grate 3  sq.  ft. 

Total  heating  surface 54  sq.  ft. 

Total  Ib.  hard  coal  fire-pot  will  hold 240  Ib. 

Total  Ib.  to  be  burned  each  test,  4-5  total 192  Ib. 

When  the  boiler-catalogs  give  these  items  and  also  the 
hours  the  boiler  is  expected  to  remain  its  rating,  and  at 
what  stack-temperature,  or  rate  of  combustion,  the  steam- 
fitter  or  the  engineer  will  be  able  to  determine  for  him- 
self the  conservatism  of  the  catalog-rating. 


ISO 


SECTION  XXV. 


The  importance  of  having  all  these  items  in  a  catalog 
is  clearly  shown  in  Table  GZ,  which  shows  the  results 
of  an  8-hr,  test  based  on  the  foregoing  data,  each  item 
showing  the  results  from  each  of  the  6  different  rates  of 
combustion. 

The  rather  startling  differences  in  the  various  "con- 
servative' ratings  which  the  same  boiler  will  afford  when 
rated  under  different  rates  of  combustion  (all  of  them 
within  the  possible  range  of  good  chimneys)  indicates 
very  sharply  why  great  care  should  be  exercised  in  the 
selecting  of  a  boiler,  to  ascertain  the  condition  of  the 
chimney  first.  (See  Sections  I  and  II  in  this  work. 
These  sections  will  prove  of  great  value  in  the  considera- 
tion of  chimney-values.)  The  strength  of  the  draft  may 
compel  the  use  of  a  boiler  rated  with  a  stack-temperature 
of  only  250  or  300  deg.  if  a  satisfactory  job  is  to  be  se- 
cured ;  or,  the  draft  may  be  so  strong  that  one  rated  under 
a  stack-temperature  of  600  or  even  800  deg.  F.  should  be 
used.  It  is  true  that  the  same  boiler  might  be  used  in 
either  case,  as  shown  by  table  GZ.  But  an  intelligent  fitter 
would  not  put  a  boiler  rated  to  carry  500  sq.  ft.  radiation 
under  a  stack-temperature  of  550  deg.  on  to  a  chimney 
that  would  not  develop  a  stack-temperature  above  225 
or  250  deg.  for  that  boiler,  and  expect  it  to  carry  its 
rating.  There  is  one  other  thing  than  can  be  developed 
from  Table  GZ.  Item  10  shows  the  total  capacity  of  the 
boiler  to  be  1,632  Ib.  of  steam.  If  this  was  all  to  be 

187 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

condensed  in  6  hours  there  must  be  272  Ib.  condensed  per 
hour,  requiring  a  rating  of  1,088  sq.  ft.  radiation,  with 
no  allowance  for  "conservatism." 

TABLE  GZ. 

Showing  the  different  ratings  the  same  boiler  will  require  to 

comply  with  the  evaporation  secured  at  various  rates 

of  combustion  and  stack  temperature. 

Item    1 — Stack  temperature,  deg.   F 750 

2 — Grate   size,   sq.   ft 3 

3 — Total   heating  surface,   sq.   ft 54 

4 — Fuel  to  be  burned,  4-5  total 192 

5 — Fuel  burned  in  1  hour,  Ib 24 

6 — Fuel  burned  per  sq.  ft.  grate  in  1  hour  (Item 

5   -r-   Item   2) 8 

7 — Lb.  water  1  Ib.  coal  evaporates 8.5 

8 — Evaporation   per   hour  per   sq.   ft.   of   heating 

surface.      Lb 3.78 

Item  5  X  Item  7 
Item  3 

9 — Evaporation  possible  from  total  heating  and 

grate  surface    , 8.5 

Item  3  X  Item  8 
Item  5 

10 — Total  Ib.  boiler  can  evaporate  from  the  full 
quantity  of  fuel  to  be  used  in  test    (Item 

4  X    Item   9) 1632 

11 — Total  evaporative  power  of  boiler  developed 

in  1  hour  from  fuel  burned  in  1  hour  (Item 

5  X  Item  9) 204 

12 — Total  radiator-rating  possible,  based  on  each 

sq.  ft.  radiator  condensing  y±  Ib.  steam  per 

hour  (Item  11  -4-  0.25) 816 

13 — "Conservative"  catalog-rating  if  15  per  cent 
is  deducted  from  the  test-showing,  as  a  fac- 
tor of  safety 694 


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A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

If  Item  10  is  divided  by  the  hours  the  boiler  is  to  be 
run  without  attention,  the  gross  rating  of  the  boiler  for 
that  number  of  hours  will  be  the  result.  Table  HZ 

TABLE  GZ. 

Showing  the  different  ratings  the  same  boiler  will  require  to 
comply  with  the  evaporation  secured  at  various  rates 

of  combustion  and  stack  temperature. 

650"  550  450  350  250 

33333 

54  54  54  54  54 

192  192  192  192  192 

21.6  19.2  16.8  14.4  12 

7.2  6.4  5.6  4.8  4 

8.5  8.5  8.5  8.5  8.5 

3.4  3.2  2.64  2.27  1.88 


8.5  •         8.5  8.5  8.5  8.5 


1632        1632         1632  1632  1632 

/ 

183         163          142  122  102 

732         652          568  488  408 

622         554          483  415  347 

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A    Practical    Manual    of    Steam    and    Hot-Water    Heating, 

shows  another  set  of  ratings  based  on  the  data  developed 
by  Table  GZ,  Item  10. 

From  the  facts  developed  in  Tables  GZ  and  HZ  in 
regard  to  the  ratings  possible  to  be  given  any  steam- 
boiler,  and  the  vital  importance  of  stack-temperature  in 
the  working  out  of  a  rating,  as  well  as  the  number  of 
hours  run  when  the  rating  was  established — Does  the 
average  catalog  leave  the  engineer  or  the  steam-fitter 

TABLE  HZ. 

Showing  the   Gross   Radiator-ratings   Required  to   Condense 
Periods,   when   the    Total    Capacity   of  the    Boiler   from 

2    Ib.      Also    "Conservative" 

Number  of  Hours  to  Main-  Pounds   of  Steam  to  be 

tain  the  Rating.  Condensed  Each  Hour. 

6  272 

7  233 

8  204 

9  181 

10  163 

11  148 

12  136 

13  129 

14  116 

15  109 

16  102 

with  anything  but  a  wild  guess  as  to  what  the  rating  may, 
or  may  not,  mean?  It  should  also  be  stated  that  these 
tables  only  contemplate  an  evaporation  of  8^  Ib.  water 
per  Ib.  coal  and  3.78  Ib.  evaporation  per  sq.  ft.  heating 
surface.  A  given  manufacturer  may  claim  to  evaporate 
6,  or  4,  or  2,  or  IV2  Ib.  water  per  sq.  ft.  of  heating  sur- 
face. The  value  of  that  surface  represented  in  radiator 
surface  condensing  l/4  Ib.  steam  per  hour  would  be,  if 

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A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

the  evaporation  is  6  Ib.  per  sq.  ft.  heating  surface,  24 
sq.  ft.  of  radiator  surface. 

If  the  evaporation  is  4  Ib.  the  radiator  capacity  is  16 
sq.  ft.  per  sq.  ft.  heating  surface.  If  the  evaporation 
is  2  Ib.  the  radiator  capacity  is  8  sq.  ft.  If  the  evaporation 
is  1^2  Ib.  per  sq.  ft.  heating  surface  the  radiator  capacity 
is  6  sq.  ft.  Therefore  the  capacity  of  a  boiler  claimed  by 
the  manufacturer  to  contain  100  sq.  ft.  of  heating  surface 

TABLE  H  Z. 

the   Steam   Produced  by   a   Boiler  for   Different   Hourly 

One    Full    Charge    of    Fuel    is    1,632    Ib.      Gage-Pressure 

Catalog-Ratings    for    Same. 

Total    Sq.    Ft.    Radiator    Surface  "Conservative"  Catalog 

Condensing  %  Ib.  Steam  per  Rate,   85%   of 

Sq.  Ft.  to  Condense  the  Amount.  Total. 

1088  925 

932  792 

816  694 

724  615 

652  554 

592  503 

544  462 

516  439 

464  395 

436  370 

408  347 

may  be  entitled  to  a  rating  of  2,400  sq|  ft.  of  radiating 
surface ;  it  may  not  be  entitled  to  over  600  sq.  ft.  rating, 
or  an  evaporative  value  of  ll/2  Ib.  per  square  foot  of 
heating  surface,  or  it  may  be  at  any  point  between. 

The  present  method  of  cataloging  house-heating  boil- 
ers does  not  enable  one  to  come  much  nearer  the  real 
facts  regarding  the  goods  than  a  rough  guess.  If  you 
guess  correctly,  you  are  satisfied.  If  you  guess  wrong, 

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A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

somebody    suffers ;   usually   the    owner   and    contractor ; 
once  in  a  great  while  the  manufacturer. 

It  may  be  claimed  that  as  the  catalogs  all  give  the 
grate  size,  the  guess  cannot  be  far  wrong  as  to  the  cor- 
rectness of  the  catalog  rating.  I  am  not  raising  the 
question  of  the  correctness  of  the  ratings.  I  will  con- 
cede that  there  is  not  one  boiler  on  the  market  today 
that  is  not  correctly  rated.  But  how  is  it  rated,  at 
what  rate  of  combustion,  or  for  how  many  hours'  run 
without  attention,  or  at  what  stack-temperature  must 
it  be  run  ?  All  these  vital  points  must  be  guessed  at, 
until  the  manufacturers  see  fit  to  give  out  the  items. 

To  illustrate  this  point.  One  boiler  that  has  been  on 
the  market  for  a  long  time  has  a  catalog  rating  of  500 
sq.  ft.  The  catalog  says  the  boiler  has  2  $4  sq.  ft.  grate, 
and  84  sq.  ft.  of  fire  surface.  The  catalog  of  another 
equally  popular  boiler  with  a  rating  of  504  sq.  ft.  claims 
3.6  sq.  ft.  grate.  One  very  popular  boiler  now  on  the 
market  and  rated  at  550  sq.  ft.  for  steam  is  claimed  to 
have  3.2  sq.  ft.  grate  and  41  sq.  ft.  of  heating  surface, 
while  still  another  cataloged  at  700  sq.  ft.  steam-radiator 
capacity  has  a  grate  surface  of  3  sq.  ft.  and  45  sq.  ft. 
of  heating  surface ! 

It  will  not  require  a  long  study  of  Tables  GZ  and  HZ, 
and  the  text  which  explains  them,  to  realize  that  the 
present  catalog-method  regarding  boiler  data  is  like 
Carlyle's  definition  of  axioms.  "Words !  Words!  High 
air-castles  cunningly  built  of  words ;  the  words  well 
bedded  in  good  logic-mortar ;  wherein,  however,  no 
knowledge  will  come  to  lodge/'  Each  of  the  boilers 
just  mentioned  is  manufactured  by  a  prominent  con- 
cern of  high  standing.  The  East,  West  and  Middle- 
West  are  represented  in  the  four  boilers  mentioned. 

192 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

If  a  contractor  has  to  furnish  a  client  a  steam-job  and 
the  requirements  are  that  he  shall  supply  steam  con- 
tinuously from  6  p.  m.  to  8  a.  m.  the  next  day  for  an 
average  amount  of  300  sq.  ft.  of  radiation,  will  the 
data  given  as  to  either  of  these  boilers  give  the  con- 
tractor the  slightest  assistance  in  selecting  the  boiler? 
Suppose  an  examination  of  the  proposed  flue  shows  a 
weak,  sluggish  draft,  so  that  only  a  very  low  stack- 
temperature  can  be  secured,  which  boiler  should  he 
select,  having  only  the  usual  catalog  ratings  to  guide 
him?  Here  are  4  boilers,  each  with  practically  the 
same  grate  surface  relative  to  the  claimed  heating  sur- 
face, each  produced  by  very  reputable  concerns,  yet 
none  of  -them  now  give,  nor  have  they  ever  given,  in 
their  catalogs,  the  data  which  can  enable  any  one  to 
make  an  intelligent  selection  in  a  case  of  this  sort.  Un- 
doubtedly the  reason  for  this  condition  lies  in  the'  fact 
that  it  is  only  within  a  very  few  years  that  the  manu- 
facturers of  boilers  gave  up  the  practice  of  making  the 
plans  for  all  the  jobs  into  which  their  product  entered, 
and  it  was  not  thought  to  be  good  business  policy  to 
let  the  public  know  all  about  their  goods.  Each  manu- 
facturer stood  behind  his  own  goods  with  his  personal 
garantee  that  the  rating  was  a  correct  one,  and  each 
felt  that  that  was  all  that  the  public  need  to  ask.  Under 
the  old  methods  they  may  have  been  justified  in  taking 
that  position.  But  now  that  they  have  thrown  the 
burden  of  the  garantee  of  the  working  of  the  boiler, 
and  the  job,  on  to  the  engineer  or  the  steam-fitter,  these 
latter  have  a  just  claim  to  be  furnished  all  the  facts  in 
relation  to  the  ratings  of  the  boilers  offered  for  sale. 


193 


SECTION  XXVI. 


Until  this  is  done,  the  whole  heating  fraternity  must 
continue  to  trust  to  luck  in  selecting  a  boiler,  or  else 
enter  into  a  long  and  often  fruitless  correspondence 
with  the  producers  of  heating  boilers.  Because  of  the 
new  conditions,  established  by  the  manufacturers  them- 
selves when  they  established  the  new  ratings,  the  rules 
for  the  figuring  for  radiation,  which  were  applicable  to 
the  old  ratings,  become  useless  for  the  man  who  desires 
to  do  reliable  work.  In  fact,  the  change  practically 
forces  every  man  in  the  business  to  get  busy  and  learn 
the  inside  working,  the  why,  and  wherefore  of  boiler 
rating,  in  order  to  protect  himself.  It  is  quite  certain 
that  there  are  boilers  on  the  market  that  the  manufac- 
turers thereof  do  not  care  to  state  in  their  catalogs  the 
basis  of  their  rating  in  full,  or  even  to  give  out  enough 
information  to  be  of  much  value  to  the  average  buyer. 
But  when  the  manufacturers  adopted  the  new  ratings 
in  1903  they  also  forced  upon  themselves,  and  the  trade, 
the  present  situation. 

The  new  conditions  compel  the  engineer  and  the 
steam-fitter  to  study  the  heating  question  from  a  point 
of  view  new  to  many,  if  not  to  all  of  them.  The  boiler- 
rating  no  longer  is  large  enough  to  cover  the  piping 
and  all  sorts  of  shortcomings.  The  burden  of  selection 
and  garantee  no  longer  rests  upon  the  manufacturer. 
He  has,  therefore,  no  longer  the  moral  right  to  withhold 
from  the  men  ^vhom  he  has  forced  to  take  the  responsi- 
bility, all  the  essential  facts  in  regard  to  the  goods  pro- 
duced. 

194 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

If  a  boiler  requires  a  stack-temperature  of  700  deg.  F. 
in  order  to  deliver  its  rating,  the  man  who  is  to  put  that 
boiler  into  a  job  and  must  garantee  its  performance, 
certainly  is  entitled  to  know  of  such  an  important  con- 
dition. If,  on  the  other  hand,  the  boiler  requires  a  low 
stack-temperature,  but  the  fire-pot  will  only  carry  fuel 
for  a  6-hour  run  at  its  rating,  the  man  who  has  the 
burden  of  making  the  job  hold  steam  for  perhaps  10 
hours,  should  know  that  the  rating  is  for  6  hours,  and 
also  on  what  kind  of  stack-temperature  the  rating  is 
based. 

The  manufacturers  have  transferred  the  most  of  the 
responsibility;  they  should  now  transfer  all  the  facts  in 
regard  to  the  rating  of  the  boilers  they  produce. 

While  considerable  information  in  regard  to  boiler- 
ratings  has  already  been  developed  in  this  discussion,  it 
i;s  evident  that — 

When  two  boilers  with  nearly  4  sq.  ft.  of  grate  sur- 
face and  full  84  sq.  ft.  of  claimed  heating  surface  are 
rated  for  500  ft.  of  steam-radiation — 

And  another  boiler,  made  by  a  manufacturer  as  honest 
and  reliable  as  the  makers  of  the  two  mentioned,  rates 
a  boiler  with  only  3  sq.  ft.  of  grate  and  about  40  claimed 
sq.  ft.  of  heating  surface  to  carry  500  sq.  ft.  of  steam- 
radiation — 

While  another,  whose  standing  and  reputation  is  the 
equal  of  either  of  the  others,  gives  a  rating  of  700  sq. 
ft.  to  a  boiler  with  a  grate  of  3^  sq.  ft.  and  a  claimed 
heating  surface  of  45  sq.  ft.  - 

There  must  be  other  things  to  consider  than  the  simple 
question  of  grate  and  heating  surface  that  the  boiler  sales- 
men mostly  talk  about.  But  it  will  be  well  to  examine  into 
this  matter  of  grate  and  heating  surface  in  order  to  more 

A  195 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

fully  explain  the  necessity  for  one  producer  to  put  84  sq. 
ft.  heating  surface  into  a  boiler  rated  for  500  sq.  ft., 
while  another  can  get  the  same  results  with  about  one- 
half  the  amount. 

There  has  been  much  less  change  in  the  construction 
of  house-heating  boilers  from  cast-iron,  between  those 
of  the  earliest  types  and  the  very  latest,  than  many 
fitters  think.  In  Fig.  17  is  shown  the  "Brayton  Cast- 
iron  Sectional  Steam-Boiler"  which  was  the  first*  steam- 


The  first  Gasf-lnn  Vertical  Section  Heafmq  Boilir  irftft  Ftirts  Bolted  Ttxftfncr     "The 
Prayton?  tnctea  in  Providence,  /U  f  in  l»6t  t>y  bcorqt  B  Brayton 

Fig.   17. 

heating  boiler  made  of  cast-iron  with  its  sections  bolted 
together  after  the  modern  fashion.  This  boiler  was  a 
good  many  years  in  getting  recognition  from  the  public. 
It  was  first  designed  as  a  power-boiler  in  1849,  and  the 
shape  of.  the  cast-iron  heating  surface  has  never  been 
materially  changed  to  this  day.  With  the  necessary 
changes  to  adapt  it  to  heating  a  building,  such  as  the 
brick-setting,  and  the  other  minor  changes  such  as  would 
be  made  today  in  fitting  a  locomotive-boiler  for  house- 

196 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

heating  purposes  (for  the  original  boiler  was  mounted 
on  a  locomotive)  Mr.  Brayton  attempted  to  use  the  boiler 
for  heating  buildings,  but  he  met  with  tremendous  oppo- 
sition. The  wrought-iron  boiler-manufacturers  fought 
him  at  every  step.  The  public  were  slow  to  believe  that 
the  cast-iron  surfaces  could  be  safe.  Mr.  Brayton,  how- 
ever, had  the  courage  born  of  knowledge  and  conviction, 
coupled  with  an  indomitable  desire  to  prove  the  correct- 
ness of  his  theory  that  cast-iron  was  the  cheapest  and 
safest  material  for  heating  boilers.  It  was  not  until  1863 
or  1864  that  Mr.  Brayton  secured  a  contract  to  put  one 
of  his  large  cast-iron  boilers  into  a  building  in  a  city  of 
some  size.  At  this  time,  he  entered  into  a  contract  to 
place  one  of  his  boilers  into  a  large  building  located  in 
one  of  the  principal  streets  of  the  city  of  Providence,  R.  I. 
The  proposition  created  a  tremendous  discussion  in  the 
city.  The  wrought-iron  boiler-men  insisted  that  the  boiler 
if  put  in  operation  would  be  a  menace  to  life  and  property. 
Finally,  the  city  authorities  appointed  "a  special  commit- 
tee of  scientists  to  investigate  the  character  of  the  new 
construction  in  order  that  the  safety  of  the  citizens  should 
be  protected."  When  the  committee  met,  Mr.  Brayton 
suggested  to  them  "that,  in  order  to  show  them  the  entire 
safety  of  the  boiler  he  proposed  to  heat  the  boiler  red- 
hot  from  the  absence  of  water  and  then  to  cool  it  down 
to  its  regular  conditions  of  action,  by  pumping  cold  wa- 
ter," asserting  that  it  could  be  done  without  danger.  The 
committee  rather  objected  to  this,  but  proceeded  to  give 
the  boiler  a  most  thorough  testing,  and  finally  reported 
so  strongly  in  favor  of  the  boiler  that  the  city  authorities 
granted  a  permit  for  its  use  at  any  point  within  the  city 

limits. 

* 

In  1865  the  Massachusetts  Mechanics'  Association,  at 

197 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

the  American  Institute  Fair,  awarded  to  this  boiler  the 
highest  award  it  could  bestow. 

The  public  were  not  yet  convinced  that  a  cast-iron 
steam  boiler  was  safe,  for  at  this  time  it  must  be  remem- 
bered that  60-lb.  pressure  was  the  usual,  and  125  Ib.  to 
200  Ib.  not  unusual  as  the  pressure  carried  on  steam- 
boilers.  The  heating  of  buildings  with  steam  had  not  yet 
become  common. 

In  1868  the  Brayton  boiler  was  tested  by  the  then  ablest 
associated  body  of  scientists  in  the  country — The  Com- 
mittee of  Science  and  Arts  of  the  Franklin  Institute  of 
Pennsylvania.  The  report  of  the  committee  on  this  Bray- 
ton  boiler  is  in  many  ways  a  remarkable  production. 
After  Mr.  Brayton  had  established  the  -safety  of  his 
boiler  he  sold  the  patents  he  held  on  it  and  the  patterns 
for  making  the  castings  to  the  Exeter  Machine  Works, 
of  Exeter,  N.  H.,  who  changed  its  name  to  the  "Exeter" 
boiler.  Under  this  name  the  boiler  has  had  an  envfable 
sale  and  record  in  New  England,  New  York,  and  Penn- 
sylvania as  a  power-boiler  and  as  a  heating  boiler,  espe- 
cially on  blower-systems  of  heating.  The  "Exeter"  was 
entered  in  the  International  Exhibition  held  at  Phila- 
delphia, Pa.,  in  1876,  and  again  at  the  Chicago  exposi- 
tion, or  World's  Columbian  Exposition  in  1893.  In  each 
case  this  original  type  of  cast-iron  boiler  made  a  most 
creditable  showing.  The  history  of  this  typical  boiler 
would  not  be  complete  without  a  short  extract  from  the 
official  report  of  a  committee  of  the  Franklin  Institute  of 
the  State  of  Pennsylvania,  to  whom  the  Exeter  Machine 
Works  sent  one  of  their  boilers  for  examination  as  to 
its  safety  from  explosions.  Remember  that  the  Exeter 
and  the  Brayton  boiler  are  .the  same  in  construction. 
The  committee  said  in  part :  "The  Exeter  Sectional  Boiler 

198 


A    Practical    Manual    of    Steam    and    Hot- Water    Heating 

comes  very  near  to  it,  if  it  does  not  solve  the  difficult 
problem  of  uniting  small  compartments  composing  a 
boiler  of  considerable  size,  and  at  the  same  time  provide 
for  the  free  escape  of  steam  without  lifting  the  water. 
Many  sectional  boilers  are  so  constructed  in  combining 
their  parts  as  to  cause  the  steam  generated  in  the  lower 
portion  of  the  apparatus  to  force  its  way  in  zigzag 
courses  through  a  whole  neighborhood  of  narrow  pas- 
sages or  through  a  number  of  long,  comparatively  small, 
and  nearly  horizontal  tubes,  into  which  it  is  quite  im- 
possible for  the  water  to  promptly  follow,  as  it  should 
do  in  order  to  maintain  perfect  circulation,  and  take  up 
all  the  transmitted  heat  before  effecting  its  escape.  In 
many  cases  these  upper  sections  are  alike  subjected  to 
the  direct  action  of  fire,  and  become,  under  a  moderate 
supply  of  steam,  highly  heated,  rendering  them  liable 
to  fracture,  without  increase  of  pressure  from  sudden 
changes  in  the  height  of  the  water. 

"The  water  in  the  'Exeter'  section  exists  in  vertical 
masses,  about  3%  in.  square  and  28  in.  high,  a  form 
favorable  to  the  ready  liberation  of  the  steam  to  and 
from  the  surface  of  the  water,  and  securing  at  the  same 
time  prompt  circulation  and  supply  of  water  to  the 
heated  surfaces  of  the  boiler." 

That  portion  of  the  above  report  which  refers  to  the 
construction  of  water-ways  in  boilers  has  not  lost  any  of 
its  force,  or  truth,  in  the  years  that  have  passed  since 
1870.  Perhaps,  at  this  time  there  are  some,  so-called, 
new  boilers  on  the  market  that  provide  a  splendid  exam- 
ple of  the  type  of  construction  that  "causes  steam  to 
zigzag  its  way  through  passages  that  the  water  cannot 
promptly  follow." 


199 


SECTION   XXVII.^ 


I  am  giving  this  condensed  history  of  the  first  suc- 
cessful construction  of  a  cast-iron  vertical-section  boiler, 
with  the  sections  bolted  together,  because,  in  its  general 
idea  of  construction,  only  a  very  few  manufacturers  have 
improved  upon  it,  except  in  some  detail  of  waterways  or 
other  interior  arrangement. 

Until  a  very  recent  period,  practically  every  producer 
of  cast-iron  boilers  retained  the  idea  of  the  separately- 
connected  steam-dome,  and  the  so-called  mud-drums,  as 
first  produced  in  the  Brayton  boiler. 

Another  reason  is  that  Brayton  has  never  received  the 
full  credit  for  which  his  devotion  to  the  principle  that 
cast-iron  was  safer  than  wrought-iron  for  house-heating 
boilers  entitles  him.  Some  recent  writers,  in  fact,  have 
given  the  credit  to  Samuel  Gold,  who  produced  the  sec- 
ond type.  This  is  only  an  improvement  of  the  Brayton 
boiler.  (See  Fig.  29,  page  330.)  Samuel  Gold  was 
not  granted  a  patent  on  the  Gold  boiler  until  the  summer 
of  1869,  or  four  years  after  the  Brayton  boiler  had  re- 
ceived the  highest  award  that  the  Massachusetts  Me- 
chanics' Association  could  bestow.  But  this  fact  should 
not  dim  in  the  slightest  the  honor  that  rightfully  be- 
longs to  Samuel  Gold.*  To  the  writer's  mind,  it  does  not 
appear  that  those  who  have  preceded  him  as  writers  on 
this  subject  have  given,  as  a  rule,  to  Samuel  Gold  the 
commanding  place  in  the  early  history  of  the  steam- 
heating  that  is  his  rightfully.  From  a  business  point  of 
view,  Mr.  Gold  was  very  fortunate  in  the  selection  of 

*Further  analysis  of  Mr.    Gold's  original  patent  is  presented  on 
pages  329  and  330. 

200 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

his  manufacturing  sales-agent.  He  selected  H.  B.  Smith 
&  Co.,  Westfield,  Mass.,  who  decided  to  push  the  boiler, 
in  conjunction  with  the  Gold  pin-radiator,  as  being  the 
most  suitable  for  house-heating  work.  That  they  were 


Fig.    18.     Gold's   Sectional    Boiler. 

correct  in  their  judgment  is  evidenced  by  the  great  popu- 
larity of  the  combination  and  the  further  fact  that  its 
introduction  as  a  low-pressure  steam-heating  system  with 

201 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 


indirect  cast-iron  radiators,  not  only  caught  the  public 
fancy,  but  practically  changed  the  entire  heating  methods 


Fig.    19.      First  Single-Pipe  Steam   System 
Used  in   Low- Pressure  Work. 

202 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 


of  the  whole  country.     But  it  was  H.  B.  Smith  &  Co. 
that  stood  in  the  lime-light  of  public  knowledge  of  the 


Fig.    20.      Mill's   Original    Safety    Boiler. 

Gold  boiler  and  the  Gold  pin-radiator,  and  not  Samuel 
Gold,  the  inventor. 

203 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

No  one  can,  or  would  even  try,  to  detract  in  the  slight- 
est degree  from  the  glory  of  achievement  due  to  J.  J. 
Walworth  and  Joseph  Nason,  as  the  first  engineers  to 
demonstrate  the  use  of  steam  as  a  practical  means  of 
heating.  But  as  a  historical  statement,  we  must  not 
lose  sight  of  the  fact  that,  notwithstanding  that  Wal- 
worth and  Nason  were  without  question  the  originators 
of  the  process  of  heating  buildings  by  steam,  Samuel 


Fig.  23.     The  Harrison   Boiler. 

Gold  was  the  first  inventor,  in  this  country  at  least,  to 
devise  a  safe  and  practical  steam-heating  apparatus  for 
small  buildings  and  homes,  that  could  be  operated  with- 
out a  special  engineer,  and  with  perfect  safety,  as  the 
only  pressure  generated  was  that  caused  by  the  friction 
in  the  pipes.  This  apparatus  was  first  placed  before  the 
public  in  either  1856  or  1857  in  a  very  limited  way.  In 

204 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

1859  Gold's  system  of  steam-heating  began  to  attract 
attention.  The  radiators  were  made  of  sheet-iron  riv- 
eted. Each  radiator  was  fed  by  one  pipe  which  was  car- 
ried to  the  highest  radiator  on  the  circuit,  the  condensa- 


Fig.   21.      Mill's    Improved    Boiler. 

tion  flowing  back  to  the  boiler  automatically.  A  pipe, 
called  an  air-pipe,  was  connected  to  the  end  opposite  the 
end  at  which  the  steam  entered  the  radiator,  in  such 
manner  that  the  steam  not  condensed  in  the  radiator 
continued  on  to  the  outer  air.  Fig.  19  gives  the  idea. 

205 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

This  was  not  only  the  first  practical  and  safe  steam-heat- 
ing apparatus,  for  low,  or  non-pressure  house-heating 
work,  but  was  the  first  single-pipe  steam-system,  so  far 
as  I  have  discovered,  to  be  used  in  low-pressure  work. 

The  use  of  sheet-iron  radiators  was  furiously  attacked 
by  the  manufacturers  of  the  several  types  of  cast-iron 


Fig.   22.      Mill's   Twin    Section    Boiler. 

radiators,  or  heaters,  as  they  were  then  called,  on  the 
one  hand;  and  by  the  wrought-iron  pipe-men  on  the 
other.  The  high-pressure  steam-men  also  brought  all 
their  forces  of  ridicule  to  bear  upon  the  apparatus.  Mr. 
Gold,  however,  kept  at  his  task  and  kept  on  investigating. 
He  quickly  saw  the  value  of  T.  T.  Tasker's  apparatus  for 
returning  the  water  of  condensation  to  the  boiler  in  a 

206 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

closed  apparatus,  and  evidently  studied  Brayton's  boiler 
with  care.  While  the  public  had  accepted  his  non-pres- 
sure system  with  considerable  satisfaction,  the  great  bulk 
of  the  sheet-iron  surface  placed  in  the  rooms  caused  a 
prolonged  wail  of  protest  from  the  artistic  architect,  and 
from  the  housewife  who  had  "some  special  thing  to  put 
right  where  that  hideous  great  heating  thing  had  to  go." 
The  cry  rose  loud  from  these  quarters  to  "get  those 
unsightly  radiators  away."  In  1862  the  Nason  pipe-radi- 
ator was  put  on  the  market.  These  were  an  improve- 
ment, but  having  gained  this  much  the  cry  still  went  up 
that  some  one  should  find  a  way  to  heat  homes  with  steam 
at  a  moderate  expense,  but  without  the  use  of  direct 
radiators  in  the  rooms.  When  Samuel  Gold  brought  out 
the  improved  Gold  system,  which  included  the  new 
cast-iron  boiler  and  the  cast-iron  indirect  radiator,  known 
as  the  Gold  pin-radiator,  in  1869,  the  question  seemed 
to  have  been  solved. 

It  is  a  fair  statement  to  say  that  the  real  beginning  of 
the  general  use  of  steam  for  heating  dwelling-houses 
should  date  from  the  introduction  of  the  Gold  system. 
Fig.  18  is  an  illustration  of  the  improved  Gold  boiler  with 
the  pin-radiators  placed  in  the  hot-air  chamber. 

In  1872,  the  Mills  boiler  was  brought  out.  This  boiler 
was  constructed  under  the  patents  obtained  by  the  late 
John  H.  Mills,  of  Boston,  who  was  also  the  patentee  of 
the  Mills  overhead  system  of  steam  and  water-heating. 
The  Mills  boiler  presents  the  first  radical  change  from 
the  idea  of  construction  that  Brayton  established  in  his 
boiler  which,  as  stated,  is  now  known  and  sold  as  the 
"Exeter,"  and  which  under  that  name  held  its  own  at 
the  World's  Fair  at  Philadelphia  and  also  at  the  great 
Exposition  at  Chicago,  in  each  case  entering  the  competi- 

207 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

tion  for  high-pressure  boilers.  This  point  must  not  be 
overlooked.  The  Mills  boiler  was  also  designed  as  a 
high-pressure  boiler.  Mr.  Mills,  in  his  book  on  "Warming 
and  Ventilation  of  Buildings,"  reproduces  several  let- 
ters from  users  of  his  boilers  wherein  the  pressure  is 
stated  at  various  pressures  from  60  to  165  lb.,  the  aver- 
age being  about  100  lb. 

Figs.  20  and  21  show  the  original  and  the  improved 
form  of  Mills'  boilers.  It  will  be  well  to  study  the  Bray- 
ton  or  Exeter,  the  Gold,  and  the  Mills  boilers  with  great 
care.  With  one  exception  they  represent  the  whole  field 
of  vertical  sectional  boiler-making  in  cast-iron  designs. 
There  are  a  host  of  variations  in  the  construction  of  the 
water-ways  and  of  the  smoke  and  gas-travel ;  various,  and 
sometimes  unintelligent,  grouping  of  alleged  heating  sur- 
faces. This  is  very  evident  to  any  one  who  is  in  posses- 
sion of  any  considerable  number  of  the  boiler-catalogs  of 
different  manufacturers  for  the  past  20  or  30  years.  But 
in  them  all,  with  the  exception  of  two  or  three  which 
have  come  out  within  the  last  decade,  there  is  no  essen- 
tial change  from  the  three  distinctive  types  first  produced 
as  the  Brayton  or  Exeter,  the  Gold,  and  the  Mills.  Every 
vertical-sectional,  cast-iron  boiler  produced  in  this  coun- 
try from  1864  when  Brayton  forced  the  city  of  Provi- 
dence to  permit  the  use  of  his  cast-iron  boiler  within 
its  limits,  down  to  the  latest  line  of  boilers  are  copies  of 
the  idea  of  Brayton,  nearly  all  using  the  external  steam- 
dome  and  the  so-called '  mud-drum,  and  the  connecting 
of  each  section  as  a  separate  boiler.  Some  of  the  latest 
lines  have  the  internal  connection  used  by  Gold  in  his 
first  boiler  made  of  cast-iron. 

For  some  reason,  not  easily  discovered,  the  cast-iron 
boiler-manufacturers  have  never  taken  up,  as  their  model, 

208 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

the  Harrison  boiler.  This  boiler  was  invented  by  an 
American  engineer  of  great  ability,  Joseph  Harrison, 
Jr.,  and  is  today,  in  many  of  its  features,  the  nearest 
perfect  as  a  steam-producing  generator  of  unquestioned 
safety  that  is  produced  from  cast-iron.  It  was  first  ex- 
hibited in  England  and  won  the  highest  award  possible 
to  its  class  in  the  International  Exhibition  at  London  in 
1862.  The  invention  of  this  boiler  secured  for  Mr.  Har- 
rison the  highest  honors  it  is  possible  to  award  to  an  engi- 
neer in  this  country,  namely,  the  awarding  of  both  the 
silver  and  gold  Rumford  medals  by  the  American  Acad- 
emy of  Arts  and  Sciences.  This  distinction  did  not  come 
to  him  because  of  his  having  designed  an  11-ton  engine 
for  the  Reading  Railroad  in  1840,  or  for  building  the  St. 
Petersburg  and  Moscow  Railroad,  or  for  designing  the 
great  bridge  over  the  river  Neva.  For  none  of  these 
great  feats  of  engineering  skill  could  he  have  received 
these  medals  of  distinction.  It  was  for  the  production 
of  a  safety  steam-boiler,  that  was  safe,  that  he  was  given 
the  medals  that  classed  him  as  a  benefactor  of  the  human 
race ;  as  a  man  whose  service  to  the  world  at  large  entitled 
him  to  be  classed  with  Sir  Humphrey  Davy,  Michael 
Faraday,  John  Tyndall,  John  B.  Erricson,  George  H.  Cor- 
liss and  other  inventors  and  discoverers  of  world-wide 
fame. 

The  strange  thing  about  the  production  of  steam-boilers 
is  that  the  wrought-iron  boiler  men,  who  try  to  produce 
safety  boilers  have,  to  a  great  extent,  adopted  the  ideas 
developed  -by  Harrison  in  his  cast-iron  boiler.  Boilers  of 
the  Babcock  &  Wilcox  and  Abendroth  &  Root,  and  to 
some  extent  the  Heine  type,  all  follow  the  lines  laid 
down  by  Harrison  in  his  cast-iron  boiler,  while  the  cast- 
iron  boilers  produced  for  house-heating  have  followed 

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A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

the  ideas  of  Samuel  Gold  who,  as  we  have  seen,  took 
his  design  from  the  boiler  of  George  B.  Brayton.  It  is 
not  the  duty  of  the  writer  of  the  present  series  to  con- 
sider, at  this  time,  the  reasons  for  such  an  outcome, 
although  they  are  of  interest  to  any  student  of  the  devel- 
opment of  either  the  power-boiler,  or  the  low-pressure, 
house-heating  type  of  cast-iron  boilers. 


210 


SECTION  XXVIII. 


I  have  stated  the  general  facts  connected  with  the 
adoption  of  the  distinctive  types  concisely  in  order  to 
give  the  reader  a  clear  understanding  of  how  the  present 
types  of  boiler  came  into  prominence,  and  also  to  show 
that  it  is  not  necessary  for  an  engineer  or  a  steam-fitter 
to  have  had  an  actual  personal  experience  with  a  boiler 
designed  as  an  improvement  of  either  type,  in  order  to 
have  some  knowledge  of  its  value  when  any  such  varia- 
tion of  the  type  is  offered  to  him  for  use  on  a  given  job. 
But  in  order  for  him  to  pass  an  intelligent  judgment  on 
the  type,  he  should  possess  some  knowledge  of 
the  value  of  direct  and  indirect  fire-surface.  Whenever  a 
large  amount  of  flue-surface  is  presented,  he  must  have 
some  understanding  of  the  amount  of  friction  these  flues 
produce  and  the  draft  required  to  offset  it.  He  must 
also  know  something  as  to  the  proportionate  relation  of 
grate  to  fire-surface  and  heating  surface  that  experience 
and  experiment  have  shown  must  obtain  in  order  to 
secure  the  best  results. 

It  is  of  course  impossible  to  tell  the  real  value  of  any 
cast-iron  boiler  except  by  actual  test.  But  there  are 
enough  things  that  are  universal  and  that  in  a  greater 
or  less '  degree  must  be  found  in  any  one  of  the  types, 
either  round  or  so-called  square,  to  enable  one  to  deter- 
mine quite  well  the  probable  value  of  any  cast-iron 
boiler,  if  the  party  offering  it  for  sale  will  state  in 
definite  terms  those  points  upon  which  we  have  shown 
that  the  steam-fitter  or  engineer  is  clearly  entitled  to 
be  enlightened. 

211 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

The  very  first  thing  to  find  out  is  the  fire-pot  capacity 
in  pounds  of  hard  coal.  There  is,  so  far  as  the  writer's 
personal  observation  extends,  no  boiler-catalog  that 
states  this  all-important  fact  in  a  clear  manner.  Some 
manufacturers  give  out  enough  data  as  to  the  size  of 
the  fire-pot  to  enable  a  capable  mathematical  professor 
to  secure  an  approximate  basis  for  guesswork  as  to  the 
fuel  capacity,  but  that  is  about  all  that  can  be  secured 
from  the  average  catalog. 

The  most  complete  catalog  I  have  seen  gives  out  in  a 
very  roundabout  way  the  information  required  to  check 
up  any  statement  that  a  salesman  for  the  product  of  the 
factory  might  make.  But  to  find  what  the  fire-pot  of 
any  boiler  listed  in  this  catalog  would  probably  hold  in 
pounds  of  coal,  from  the  catalog  itself,  would  probably  be 
an  impossible  task  to  many,  if  not  a  majority,  of  the  sales- 
men who  are  calling  on  the  trade  today  in  this  country. 
The  proportion  of  architects  and  members  of  the  trade 
upon  whom  these  salesmen  call  who  could,  or  would, 
quickly  or  easily  find  and  figure  out  for  themselves,  the 
fire-pot  capacity  is  even  less. 

In  this  best  catalog,  in  order  to  find  the  coal-capacity 
of  any  one  of  the  listed  boilers  a  long  hunt  is  needed. 
In  the  printed  matter  giving  the  grate-area  in  square 
inches,  is  given  the  square  feet  in  the  fire-pot,  but  not 
the  cubic  contents.  An  item  in  the  text  indicates  that 
additional  measurements  can  be  found  in  another  por- 
tion of  the  book.  A  careful  series  of  line-drawings  in- 
dicate various  important  features  of  construction  and 
on  another  page  the  inches  applying.  From  these  it  is 
possible  to  get  the  distance  from  the  top  or  bottom  of 
the  grate  to  the  center  of  the  feed-door,  which  is  cer- 
tainly as  -high  as  any  house-owner  will  be  liable  to  feed 

212 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

his  boiler  at  any  one  firing.  Assuming,  then,  that  this 
is  the  producer's  idea  of  the  fire-pot  capacity,  we  pro- 
ceed to  multiply  the  square  inches  in  the  grate  or  fire- 
pot,  as  given  in  one  place,  by  these  new-found  figures, 
on  the  assumption  that  the  new-found  measure  is  the 
maximum  height  of  the  fire-pot,  in  order  to  get  the  cubic 
inches  supposed  to  be  in  the  space  indicated  on  the  line- 
drawing.  This  gives  us  a  measure  that  may  be  correct, 
or  may  be  quite  incorrect.  But  it  is  at  least  a  measure 
that  enables  one  to  make  a  fair  guess  as  to  the  capacity 
of  the  various  boilers  as  shown  by  these  drawings,  to 
hold  coal.  But  now  comes  a  new  difficulty.  What  kind 
and  size  of  coal  was  used  in  the  testing  of  the  boiler? 
Is  the  weight  of  a  cubic  foot  of  coal  to  be  taken  as  the 
weight  of  a  cubic  foot  of  solid  coal,  or  of  broken,  or  of 
egg,  or  of  stove,  or  of  chestnut,  or  of  pea?  They  all 
vary  in  their  weight  per  cubic  foot  of  space,  according 
to  leading  authorities.  Just  to  show  how  completely  one 
is  up  against  another  guessing  contest  in  this  boiler- 
catalog  matter,  the  moment  one  tries  to  solve  the  pub- 
lished ratings  of  house-heating  boilers,  the  following 
table  of  the  pounds  of  coal  required  to  fill  one  cubic  foot 
of  space  is  given,  also  the  cubic  feet  required  for  a  ton 
of  2,240  Ib.  and  for  2,000  Ib.  The  great  difference  in 
the  B.  t.  u.  given  off  by  different  grades  of  hard  coal  is 
zvell  known,  and  manufacturers  have  apparently  agreed 
that  good  coal  should  be  considered  to  develop  14,500 
B.  t.  u.  per  Ib.  under  laboratory  conditions.  Now  they 
should  agree  upon  the  pounds  of  hard  coal  to  be  con- 
sidered as  a  cubic  foot  when  used  in  the  nrerpots  of 
heating  boilers. 

This  table  discloses  a  difference  of  nearly  30  per  cent 
in  the  claimed  weights  of  one  average  cubic  foot  of  hard 

213 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

coal.  Supposing  a  fire-pot  of  3  cubic  feet  in  capacity. 
If  figured  on  the  basis  of  64.7  lb.,  the  full  load  is  194 
Ib.  If  taken  on  the  basis  of  50  lb.  to  the  cubic  foot, 
then  the  full  load  is  only  150  lb.  A  difference  certainly 
large  enough  in  a  small  boiler  to  cause  serious  trouble 
to  a  man  who  must  garantee  his  job  to  maintain  fire 
and  hold  steam  for  a  certain  number  of  hours.  When 

TABLE  JZ. 

Average  Average  Average 

Mine                      Lbs.  in  Cu.  Ft.  in  Cu.  Ft.  in 

or  Authority  1  Cu.  Ft.     2240  Lb.  Ton     2000  Lb.  Ton 

Average    Wilkesbarre  64.7  34.6  31.0 

Hard    Lehigh    61.9  36.2  32.4 

Average        Schuylkill 

W.  A 59.9  37.5  33.4 

Shamokin   58.2  38.5  34.4 

Lorberry     56.4  39.8  35.5 

According  to  Haswell. 

Average  all  hard  coal  56.7  39.5  35.3 

According  to  Heine. 

Average  all  hard  coal  53.4  42.0  37.5 

C.  E.  Houghtaling 

Average  all   Lehigh..   56.0  40.0  37.7 
Amer.    Radiator    Cat- 
alog. Average  all  hard 

coal,  as  about 50.0  44.8  4.0.0 

considering  the  ratings  of  cast-iron  boilers,  it  should 
not  be  overlooked  that  the  difference  in  weight  between 
the  various  commercial  sizes  required  to  fill  one  cubic 
foot  of  space  is  large,  although  not  as  great  as  has  been 
disclosed  in  the  different  hard  coal  mined  from  the  best 
hard-coal  mines. 

Take  the  Wilkesbarre  mine  as  an  illustration.     "Ac- 
cording to  measurements  made  with  Wilkesbarre  anthra- 

214 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

cite  coal  from  the  Wyoming  valley,  it  requires  32.2  cu. 
ft  .of  lump,  33.9  cu.  ft.  broken,  34.5  cu.  ft.  egg',  34.8  cu. 
ft.  of  stove,  35.7  cu.  ft.  of  chestnut,  and  36.7  cu.  ft.  of 
pea,  to  make  one  ton  of  coal  of  2,240  Ib."  (Records  of 
American  Charcoal  Iron- Workers,  Vol.  3.) 

This  means,  then,  that  1  cu.  ft.  of  Wilkesbarre  lump 
will  weigh  69.6  Ib. ;  1  cu.  ft.  of  broken,  66.07  Ib. ;  1  cu.  ft. 
of  egg,  64.92  Ib. ;  1  cu.  ft.  of  stove,  64.37  Ib. ;  1  cu.  ft.  of 
chestnut,  62.74  Ib. ;  1  cu.  ft.  of  pea,  61.04  Ib. 

It  will  be  seen  from  these  figures  that  there  are  sub- 
stantial reasons  why  the  boiler-catalogs,  under  the  pres- 
ent conditions  as  previously  described,  should  state  the 
capacity  of  fire-pots,  as  certainly  as  they  should  state 
the  heating  surface,  height  of  water-line,  or  grate-sur- 
face. 

Having  the  grate-surface,  and  the  cubic  capacity  of 
fire-pot  when  full,  the  next  thing  of  commanding  impor- 
tance, but  not  usually  given  in  catalogs,  is  the  matter 
of  heating  surface. 

This  is  one  thing  over  which  the  manufacturers  will 
honestly  differ  with  each  other,  and  members  of  the 
trade  hold  more  or  less  vigorous  opinions  as  to  the  value 
of  the  heating  surface  not  in  direct  contact  with  the 
fire.  There  are  also  many  members  of  the  trade  who 
have  quite  positive  opinions  to  the  effect*  that  it  is  im- 
possible to  get  too  much  heating  surface  in  a  boiler.  It 
is  not  the  purpose  of  these  articles  to  enter  into  an  argu- 
ment for  or  against  any  special  type  of  heating  boiler, 
or  of  the  ideas  of  any  special  producer  in  regard  to  the 
manner  of  placing  heating  surface.  Rather  is  it  to  state, 
as  clearly  as  I  can,  the  facts  derived  from  a  great  num- 
ber of  tests  made  by  others,  and  by  the  writer,  and  leave 
the  individual,  who  is  to  purchase,  install  and  garantee 

215 


A    Practical    Manual    of    Steam    and    Hot- Water    Heating 

the  working  of  any  particular  boiler,  to  make  such  ap- 
plication of  the  data  as  his  judgment  dictates.  As  has 
already  been  stated  there  is  no  one  type  of  boiler  made 
in  cast-iron  that  is  absolutely  best  to  use  for  any  and  all 
jobs.  It  is  the  intention  in  these  articles  to  so  present 
the  essential  facts  in  regard  to  the  rating  and  working 
of  the  cast-iron  heating  boiler  that  any  intelligent  and 
thoughtful  architect,  engineer,  or  steam-fitter  can,  from 
ascertained  data,  determine  from  facts,  instead  of  guess 
or  prejudice,  the  particular  boiler  best  fitted  to  do  the 
required  work  under  given  conditions. 

The  basic  ideas  embodied  by  Brayton  and  Harrison,  in 
their  original  boilers,  in  regard  to  heating  surface  in 
the  cast-iron  boiler,  have  never  been  discredited,  and  re- 
main to  this  day  as  the  form  of  structure  of  most  of  the 
boilers  produced  from  cast  iron  in  the  vertical  types. 

The  use  of  the  wrought-iron  boilers  almost  entirely 
for  heating  as  well  as  power-purposes  from  the  time  Wai- 
worth  and  Nason  first  pointed  the  way  to  the  use  of 
steam  for  house  heating,  up  to  1863,  and  to  a  very  con- 
siderable extent  to  this  writing,  has  probably  had  much 
to  do  with  the  fact  that  but  a  very  small  amount  of  data 
has  been  accumulated  and  published  in  regard  to  the 
heating  surfaces  of  the  cast-iron  boilers.  The  further 
fact,  already  mentioned,  that  almost  without  exception 
the  cast-iron  boiler  manufacturers  sold  their  product 
either  through  agents  or  direct  to  the  consumer,  in  either 
case  furnishing  the  "lay-out"  from  1863  until  within 
a  very  few  years  (indeed,  some  of  the  smaller  manufac- 
turers are  yet  doing  so)  has  made  it  a  very  easy  thing 
to  keep  this  sort  of  information  from  the-  public.  In 
some  cases  it  would  be  about  the  last  thing  that  the 
manufacturer  would  care  to  have  stated  in  regard  to 

216 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

the  product,  if  he  were  to  come  into  competition  with  a 
boiler  claiming  to  have  three  or  four  times  the  heating 
surface  he  was  claiming  for  his  own  production. 


SECTION  XXIX. 


It  is  within  the  memory  of  a  large  number  of  the 
trade  that  a  prominent  wholesale  house  in  this  country 
published,  as  illustrating  the  wonderful  heat-extracting 
power  of  the  heating  surface  in  a  cast-iron,  house-heat- 
ing boiler  they  were  offering,  a  picture  or  cartoon,  in 
which  the  boiler  was  shown  as  being  run  with  a  roaring- 
fire  in  it,  while  perched  on  the  smoke-pipe  was  a  buxom, 
naked  baby,  tagged  "Just  Comfortable!" 

It  is  perhaps  needless  to  say  that  that  especial  boiler 
was  being  praised  up  to  an  expectant,  but  ignorant  public, 
because  of  its  alleged  heating  surface  and  the  wonderful 
arrangement  of  its  flue  surface,  coupled  with  quite  ex- 
travagant claims  in  regard  to  the  coal-saving  effected. 

That  a  cartoon  of  this  sort  could  be  sent  out  by  a 
strong  and  reputable  selling  agent,  as  a  business-getter 
for  his  boiler,  indicates  how  little  the  average  person 
uses  his  reasoning  powers,  and  also  to  what  extent  the 
public  has  considered  the  requirements  of  one  feature 
of  the  matter  of  producing  steam  to  be  converted  into 
energy;  namely,  heating  surface  in  a  wrought-iron  boil- 
er, to  the  almost  total  exclusion  of  other  contributing 
features. 

There  are  some  things,  usual  in  the  care  of  and  in 
the  running  of  boilers  used  for  power-purposes,  that 
are  not  usual  in  the  care  of,  or  in  the  running  of  cast- 
iron  house  heating  boilers.  For  instance,  it  is  not  ex- 
pected that  a  fireman  shall  be  in  constant  attendance  on 
a  residence-heating  plant,  or  that  mechanical  stokers 

218 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

will  be  used,  or  that  the  boiler  shall  be  blown  off  with 
frequency,  or  that  a  feed-water  heater  shall  be  installed. 
Such  things  as  these  belong  to  the  care  of  boilers  that 
are  used  to  create  steam  that  is  to  be  stored  in  the  boiler 
under  considerable  pressure  and  then  delivered  to  an 
engine  for  its  heat-energy  to  be  reduced  to  mechanical 
power. 

With  the  pressure  at  the  boiler  limited  to  2  lb.,  it  is 
evident  that  the  steam  produced  is  not  to  be  used  for 
mechanical  power.  It  is  also  evident  that  no  great 
amount  of  the  steam  created  can  be  stored  without 
creating  a  greater  pressure  than  the  stipulated  2  lb.  At 
the  very  first,  then,  it  will  be  seen  that  a  condition  en- 
tirely different  from  that  demanded  for  a  power-boiler 
is  presented.  The  fire  is  not  to  be  fed  so  often,  yet  con- 
stant steam  is  to  be  delivered  for  8,  10  or  12  hours 
from  one  firing. 

Ordinary  common  sense  will  at  once  recognize  that 
a  larger  fire-pot  capacity  relative  to  the  heating  surface 
should  be  provided.  How  much  larger  depends  upon 
the  number  of  hours  that  the  steam  is  to  be  constantly 
furnished  at  the  2-lb.  pressure,  and  the  evaporative  val- 
ue of  the  fuel  to  be  used.  Given  a  coal  of  the  theoretical 
value  of  15,000  B.  t.  u.  and  each  pound  may  evaporate 
in  practice  8.5  lb.  water,  but  given  a  coal  that  has  a  the- 
oretical value  of  10,000  B.  t.  u.  and  the  very  best  that 
can  be  expected  in  evaporation  of  water  may  be  4.5  lb. 
to  the  pound  of  coal.  As  a  practical  proposition  the  dif- 
ference in  size  of  fire-pot  required  to  hold  an  8-hour  sup- 
ply of  fuel  for  a  run  of  8  hours  in  a  house-heating  boiler, 
using  these  two  coals  is  as  one  to  two.  If  it  required 
100  lb.  of  the  best  coal  to  produce  the  steam  it  would 
require  practically  200  lb.  of  the  poorer  grade.  And  this 

219 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

without  considering  the  question  of  heating  surface  at 
all.  As  has  been  shown,  the  total  heat  that  a  boiler 
can  in  time  develop  from  the  fuel,  and  the  hourly  ca- 
pacity of  that  boiler  are,  widely  different  propositions, 
but  in  either  case  the  evaporative  value  of  the  fuel  de- 
termines the  size  of  the  fire-pot  needed  to  hold  the  fuel 
required. 

With  the  power-boiler  the  difference  in  the  evapora- 
tion power  of  the  coal  can  be  covered  by  the  labor  of 
the  fireman  and  more  frequent  firings.  The  selection  of 
a  suitable  boiler  for  a  given  house-job  must  therefore 
be  governed  to  some  extent  by  the  kind  of  coal  that  the 
prospective  customer  intends  to  use,  and  the  number  of 
hours  it  is  required  to  hold  steam  with  one  firing  of  fuel. 

Most  heating  catalogs  contain  a  table  showing  the 
heating  and  evaporative  power  of  different  coal.  An 
examination  of  any  of  these  catalogs  will  disclose  that 
there  is  a  very  considerable  difference  between  the  coal 
mined  in  the  ea?t  and  that  from  the  western  portion  of 
the  country. 

It  necessarily  follows  that  a  corresponding  difference 
in  the  size  of  the  fire-pot  must  obtain  in  order  to  get  the 
same  results  from  one  full  load  of  fuel. 

It  will  be  found  that  not  only  are  there  very  consider- 
able differences  in  the  heating  value  of  a  pound  of  dif- 
ferent coals,  but  there  are  also  as  great  differences  in 
the  number  of  pounds  required  to  fill  a  given  space,  in 
the  western  as  in  the  eastern  coals. 

A  bushel  of  bituminous  coal  in  Pennsylvania  is  76  Ib. 
In  Indiana,  70  Ib.  In  Ohio,  Kentucky,  Illinois,  Missouri, 
and  several  other  southern  and  western  states,  80  Ib.  are 
required  for  a  bushel  of  bituminous  coal. 

A    discussion    of    the    process    of    combustion    is    not 

220 


A     Practical    Manual    of    Steam    and    Hot-Water    Heatin^ 

needed  at  this  time  perhaps,  but  it  may  be  well  to  ex- 
plain in  a  few  words  the  use  of  the  tables  of  the  heating 
and  evaporating  power  of  coals  that  are  given  in  many  of 
the  boiler-catalogs. 

The  different  manner  in  which  these  tables  are  given 
out  by  various  boiler-makers  quite  clearly  indicate 
that  it  is  not  intended  by  some  of  them  that  the  tables 
are  to  be  used  in  connection  with  the  question  of  the 
sizes  of  the  fire-pot  they  are  putting  into  their  particular 
product,  but  rather  as  a  foil  when  the  rating  of  their 
boiler  happens  to  be  questioned  in  some  soft-coal  terri- 
tory. 

A  table  of  this  sort,  to  be  of  real  assistance  to  the 
fitter,  should  give  the  average  moisture,  ash  and  volatile 
matter  contained  in  each  pound  of  a  given  coal.  A  table 
to  be  of  real  value  as  an  aid  in  selecting  a  cast-iron  house- 
heating  boiler  should  give  these  in  order  that  the  fitter 
may  find  out  the  probable  space  that  he  must  have  pro- 
vided in  the  fire-pot  for  holding  the  total  bulk  of  the 
fuel  he  intends  to  use  on  a  given  job. 

The  "combustible"  in  a  coal,  is  that  portion  that  will 
burn.  In  each  pound  there  is  a  varying  quantity  of 
earth,  ash,  water,  sulphur,  and  nitrogen  which  are  of 
little  or  no  value  as  fuel.  In  the  various  kinds  of  coal 
the  ash  and  moisture  constitute  quite  a  percentage  of 
the  total  weight.  In  good  coal  the  portion  of  what  is 
called  the  fixed  carbon  constitutes  the  largest  percentage 
of  the  weight,  and  from  it  colmes  the  largest  percentage 
of  the  heat.  In  all  coal  there  is  some  pitch,  tar,  naptha, 
and  gases  which  combine  to  produce  what  is  called"  the 
volatile  matter  in  some  tables,  and  hydro-carbon  in 
others.  It  is  the  proportion  of  fixed  carbon  arid  of  hy- 


221 


•Domestic  Engineering"  Cartoon  on  "The  ffttricacie*  of  Boiler  Rating."— No.  XIX. 


Domestic    Engineering"    Pilot-Boat   to   the    Rescue. 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

dro-carbon  in  a  coal  that  fixes  its  quality  as  hard,  anthra- 
cite, bituminous,  or  the  intervening  grades. 

Coal  containing  from  86  to  100  per  cent  of  fixed  carbon 
and  not  to  exceed  12.5  per  cent  of  hydro-carbon,  or  vola- 
tile matter,  is  sold  as  anthracite  coal  in  various  sections 
of  the  country.  Strictly  hard,  dry,  anthracite-coal 
should  contain  not  less  than  92  per  cent  fixed  carbon 
and  not  over  7.66  per  cent  of  volatile  or  hydro-carbon 
matter.  Coal,  that  shows  less  fixed  carbon  and  more  in 
volatile  matter,  should  properly  come  under  the  head 
of  either  semi-anthracite,  semi-bituminous,  or  bituminous. 
The  dividing  line  between  the  coals  is  slightly  at  vari- 
ance as  given  by  the  most  careful  writers.  The  classifi- 
cation as  given  in  the  Babcock  &  Wilcox  catalog  "Steam" 
seems  to  be  an  average  of  several.  It  is  as  follows : 

Fixed  Carbon,  Volatile  Matter, 

per  cent  of  per  cent  of 

combustible.  Combustible. 

\nthracite   100  to  92  0  to     8 

Semi-anthracite     92  to  87  8  to  13 

Semi-bituminous    87  to  75  13  to  25 

Bituminous     75  to  50  25  to  50 

Lignite    below  50  over  50 

Simply  stating  the  heating  value  of  the  coal  from  a 
given  mine,  unless  the  moisture,  ash,  and  volatile  mat- 
ters are  also  given,  does  not  give  the  man  who  must  select 
a  cast-iron  boiler,  or  any  boiler,  for  a  heating  job  that  is 
to  be  fired  only  at  intervals  of  6  or  8  or  more  hours  any- 
thing definite  upon  which  to  work. 

A  table  saying  simply  that  a  certain  coal  has  a  heat- 
ing value  of  10,000  B.  t.  u.  per  Ib.  is  interesting  as  a  state- 
ment of  fact,  but  of  what  use  will  it  be  in  deciding  as  to 
the  cubic  content  of  the  fire-pot  that  is  to  carry  coal 

223 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

enough  to  furnish  steam  steadily  for  10  hours?  The  ash 
in  coals  varies  from  less  than  2  per  cent  to  34  per  cent, 
or  more  of  the  bulk;  the  moisture  from  almost  1  per 
cent  to  over  17  per  cent;  and  no  one  expects  to  get 
heat,  to  any  great  extent,  from  ash  or  moisture.  Shall 
we  assume  that  these  tables  are  giving  the  B.  t.  u.  in  a 
Ib.  of  combustible?  If  so,  then  one  must  guess  at  the 
amount  of  ash  and  moisture  And  why  not?  The  cast- 
iron  boiler  manufacturers  compel  the  fitter  to  guess  at 
many  of  the  most  important  things  connected  with  the 
selection  of  a  boiler  so  far  as  any  information  is  to  be 
found  in  their  present  catalogs.  That  is,  most  of  them 
do.  Another  guess  cannot  leave  the  poor  fitter  much 
worse  off. 

But  if  the  10,000  B.  t.  u.  represents  the  heat  in  a  pound 
of  the  coal  as  it  comes  from  the  mine,  what  else  does  it 
contain?  Is  the  ash,  for  instance,  10  or  30  per  cent  of 
the  pound?  How  much  fixed  carbon  is  in  that  pound 
of  coal?  How  can  one  find  out  from  the  statement  how 
many  pounds  of  that  coal  it  will  take  to  fill  the  fire- 
pot  of  any  boiler? 

When  a  table  gives  the  moisture,  ash,  fixed  carbon, 
and  the  evaporative  power  of  one  pound  of  the  coal,  dry 
and  free  from  ash,  you  can  seem  to  get  at  something  to 
base  a  reasonable  guess  upon.  I  am  not  claiming  that 
a  positive  certainty  can  be  secured,  but  a  basis  can  be 
laid  that  will  enable  one  to  place  a  factor  of  safety  with 
a  fair  prospect  of  securing  a  boiler  that  would  give  sat- 
isfaction with  the  coal  to  be  used.  To  make  this  quite 
clear,  take  as  an  illustration  two  jobs,  each  of  which  is 
to  furnish  125  Ib.  of  steam  per  hour  for  8  hours  with  one 
firing.  One  is  to  use  a  high  grade  of  anthracite  coal. 
The  other  an  Ohio  coal  of  average  quality.  How  many 

224 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

cubic  feet  of  space  will  be  theoretically  required  to  hold 
enough  of  each  coal  to  probably  produce  the  steam? 

This,  as  will  be  seen,  does  not  touch  the  question  oi 
the  heating  surface  or  any  of  the  things  which  go  to 
make  efficiency  in  a  boiler.  We  can  take  those  up  later ; 
what  we  want  now  is  to  find  out  something  about  fire- 
pot  capacity  required  for  these  two  coals  in  order  tc 
know  how  to  select  a  proper  boiler  fire-pot  for  each,  so 
far  as  that  one  feature  is  concerned.  Hunting  up  a  cata- 
log that  tells  the  whole  of  the  story  of  an  analysis,  we 
may  find  that  the  anthracite  coal  is  listed  as  having  3.42 
per  cent  moisture,  4.38  per  cent  volatile  matter,  83.27 
per  cent  fixed  carbon,  8.20  per  cent  ash,  and  14,900  B. 
t.  u.  per  pound  of  combustible.  Taking  this  data  and 
deducting  the  moisture  3.42  per  cent  and  the  ash  8.20 
per  cent  or  11.62  per  cent  of  the  pound  which  has  no 
heating  value,  we  find  that  only  about  88  per  cent  (100 — 
11.62  per  cent=88.38  per  cent)  of  this  coal  as  it  enters 
the  furnace  is  combustible,  or  13,112  B.  t.  u.  (14900  X 
.88  ==  13112). 

All  of  this  88  per  cent  is  not  available,  for  at  least 
25  per  cent  of  the  combustible  in  hard  coal  and  from 
35  to  50  per  cent  of  the  total  combustible  in  bituminous 
coal  is  required  to  supply  the  loss  through  imperfect 
combustion,  radiation  from  the  boiler  itself  and  the 
chimney-draft,  and  often  other  losses.  It  is  usual  to 
consider  the  sum  of  these  losses  from  the  best  of  anthra- 
cite coal  as  25  per  cent  of  the  net  combustible.  Making 
this  allowance  for  coal  we  are  considering,  we  have  left 
for  the  production  of  steam  9,834  B.  t.  u.  from  each 
pound  of  the  coal.  As  996  B.  t.  u.  are  required  to  pro- 
duce one  pound  of  steam  from  and  at  212  deg.  F,  it  fol- 
lows that  each  pound  of  this  coal  should  produce  a 

225 


A    Practical    Manual    of    Steam    and    Hot- Water    Heating 

trifle  over  10  Ib.  of  steam  (9834 -r- 966  =  10.1).  We 
have  to  provide  for  125  Ib.  of  steam  each  hour  for  eight 
consecutive  hours  with  one  firing  of  coal,  or  for  1,000 
pounds  of  steam.  To  supply  this,  with  no  extra  allow- 
ance for  extra  waste  or  for  renewal,  will  demand  the 
supply  of  100  Ib.  of  this  quality  of  coal. 


SECTION  XXX. 


Turning  to  table  J  Z  we  find  that  it  will  require  any- 
where from  50  to  65  Ib.  of  anthracite  coal  to  fill  1  cu.  ft. 
of  space.  At  60  Ib.,  which  is  about  the  average  weight 
claimed  by  the  mines  as  the  weight  of  a  cubic  foot,  the 
100  Ib.  required  will  occupy  1.2-3  cu.  ft.  of  space.  If  we 
use  the  average  of  weight  given  by  the  outside  authori- 
ties given  in  that  table,  or  54  Ib.,  it  will  icquire  1.85 
cu.  ft.  If  we  use  the  lowest  average  weight  as  given 
in  the  table  is  will  require  2  cu.  ft.  These  are  for  an 
8-hour  run.  If  the  run  is  to  be  for  6  hours  a  smaller 
space  would  be  required,  and  if  for  10  or  12  hours  more 
cubic  space  must  be  provided. 

Now  let  us  examine  the  other  boiler  for  which  an 
Ohio  coal  is  to  be  used  for  fuel.  The  conditions  are  to 
be  the  same,  an  8-hour  run  with  one  firing.  We  may  find 
that  the  Ohio  coal  has  the  following  data  given  as  to 
its  value :  Moisture,  5  per  cent ;  volatile  matter,  35.65 
per  cent. ;  fixed  carbon ,  53.15  per  cent. ;  ash,  9.1  per 
per  cent ;  and  the  heating  value  of  1  Ib.  of  combustible, 
14,200  B.  t.  u.  The  ash  and  moisture  equal  14  per 
cent  of  each  pound ;  therefore,  the  coal  as  it  would  enter 
the  furnace  contains  only  86  per  cent  of  a  pound  of 
combustible,  or  12,212  B.  t.  u.  Owing  to  the  high  per- 
centage of  hydro-carbon,  or  volatile  matter,  present  in 
this  coal,  and  which  is  very  difficult  to  keep  in  a  state 
of  combustion  in  actual  practice,  experiment  has  demon- 
strated that  a  much  larger  loss  of  the  theoretical  value 
in  B.  t.  u,  is  sustained  from  coal  with  a  large  percentage 

227 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

of  hydro-carbons  than  occurs  in  the  anthracite  coal.  In 
fact,  it  is  so  difficult  to  keep  the  coal  in  such  a  state  of 
perfect  combustion  as  will  ignite  all  these  gases  before 
they  pass  to  the  chimney,  that  the  losses  through  im- 
perfect combustion,  radiation  jrom  the  boiler  itself,  the 
chimney-draft  and  other  losses  are  in  actual  tests  on 
working  jobs  never  less  than  35  per  cent  and  they 
sometimes  reach  over  50  per  cent,  when  the  volatile 
matter  is  in  a  high  ratio  to  the  fixed  carbon.  The  fig- 
ures given  for  the  coal  we  are  considering  indicate  that 
under  good  working  conditions  that  instead  of  the  25  per 
cent  that  we  allowed  for  these  losses  in  the  hard-coal 
boiler-case,  that  we  should  allow  in  this  case  at  least 
40  per  cent  for  them.  We  have  12,212  B.  t.  u.  from 
which  to  take  this  40  per  cent,  leaving  us  for  steam- 
production  7,327  B.  t.  u.  Dividing  this  by  the  heat 
units  required  to  produce  one  pound  of  steam  966  B.  t. 
u.  and  we  have  the  steam  value  of  the  coal  at  7.6  Ib.  per 
pound  of  coal.  To  produce  the  1,000  Ib.  of  steam  re- 
quired to  run  for  8  hours,  we  must  burn  132  Ib.  of  this 
coal  in  the  8  hours.  A  cubic  foot  will  weigh  53  Ib., 
although  one  catalog  gives  the  average  weight  of  soft 
coal  as  40  Ib.  4t  53  Ib.  per  cu.  ft.,  the  boiler  which  is 
to  use  this  Ohio  coal  must  furnish  2.5  cu.  ft.  to  just 
contain  the  coal  for  an  8-hour  fire,  with  no  allowance 
for  extra  waste  or  renewal.  The  boiler  that  was  to  use 
hard  coal  we  found  must  have  1.2-3  cu.  ft.  of  space.  The 
difference  in  space  required  for  the  hard  coal  and  that 
required  for  the  soft  coal  used  for  the  illustration  is 
practically  51  per  cent. 

It  may  be  argued  that  in  making  this  illustration  that 
I  have  used  extremes  of  hard  and  soft  coal-values, 
but  a  closer  examination  of  the  combustible  value  will 

228 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

disclose  that  the  hard-coal  sample  was  held  at  14,900 
B.  t.  u.  per  pound  of  combustible  and  the  soft  coal  at 
14,200  B.  t.  u. 

Many  people  confound  the  semi-anthracite  coals  with 
the  bituminous  coals.  There  are  also  many  who  say 
that  soft  coal  cannot  be  used  in  house-heating  boilers 
because  they  will  not  hold  steam  long  enough  for  an  8 
or  10-hour  run.  In  this  they  are  in  error. 

Given  a  suitable  chimney  and  sufficient  draft,  with  a 
fire-pot  large  enough  to  hold  the  quantity  of  fuel  re- 
quired, soft  coal  can  be  used  with  as  much  certainty  of 
satisfaction  as  can  anthracite,  providing  care  is  taken 
to  keep  the  boiler-surfaces  and  the  stack  free  from  the 
accumulations  of  soot. 

This  soot  is  in  reality  largely  composed  of  the  volatile 
matter,  or  the  hydro-carbons,  of  the  coal  which  did  not 
become  ignited.  Kent,  page  620,  says :  "If  mixed  on 
their  first  issuing  from  amongst  the  burning  carbon  with 
a  large  quantity  of  hot  air,  these  inflammable  gases  are 
completely  burned  with  a  transparent  blue  flame,  pro- 
ducing carbonic  acid  and  steam.  When  mixed  with  cold 
air  they  are  apt  to  be  chilled  and  pass  off  unburned. 
When  raised  to  a  red  heat,  or  thereabouts,  before  being 
mixed  with  a  sufficient  quantity  of  air  for  perfect  com- 
bustion, they  disengage  carbon  in  fine  powder  and  pass 
to  the  condition  partly  of  marsh  gas  and  partly  of  free 
hydrogen ;  and  the  higher  the  temperature,  the  greater 
the  proportion  of  carbon  thus  disengaged.  If  the  disen- 
gaged carbon  is  cooled  below  the  temperature  of  igni- 
tion before  coming  in  contact  with  oxygen,  it  constitutes, 
while  floating  in  the  gas,  smoke,  and  when  deposited  on 
solid  bodies,  soot." 

As  stated,  many  people,  including  a  number  of  boiler- 

229 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

manufacturers,  confound  the  semi-bituminous  with  the 
bituminous  coal. 

Just  to  show  the  difference,  so  far  as  boiler  selection 
is  concerned,  let  us  take,  as  an  illustration,  a  sample  from 
Pocahontas,  Va.,  and  one  of  the  New  River,  W.  Va., 
mines  and  compare  the  cubic  space  required  for  an  8- 
hour  run  with  the  results  we  have  already  found  neces- 
sary for  anthracite  and  real  soft  coal. 

Take  Pocahontas  first.  The  proximate  analysis  show 
that  this  coal  has  1  per  cent  moisture,  21  per  cent  vola- 
til  matter,  74. 39  per  cent  fixed  carbon,  3.03  per  cent 
ash ;  heating  value  per  pound  of  combustible,  15,700 
B.  t.  u. 

The  ash  and  moisture  equals  4.3  per  cent  of  each 
pound  of  coal  as  it  enters  the  furnace,  therefore  only 
05.7  per  cent  of  the  total  is  combustible,  or  15,025  B. 
t.  u.,  which  are  available  for  all  purposes.  This  coal  hav- 
ing 22.5  per  cent  of  volatile  matter  in  its  combustible 
will  lose  more  by  means  of  imperfect  combustion  and 
chimney-draft  than  would  anthracite,  while  the  other 
losses  wrould  without  doubt  be  fully  as  large.  From  the 
results  derived  from  many  experiments  it  has  been  found 
that  under  the  most  favorable  conditions  that  these  losses 
average  for  the  very  best  grade  of  semi-bituminous  coal 
at  least  35  per  cent  of  the  total  available  B.  t.  u.  in  each 
pound.  In  this  case  then  it  would  mean  35  per  cent  of 
15,025  B.  t.  u.,  or  5,259  B.  t.  u.  As  it  takes  966  B.  t.  u. 
to  create  1  Ib.  steam  from  and  at  212  deg.,  it  follows  that 
this  coal  will  produce  10  Ib.  of  steam  per  pound  of  coal. 
Therefore,  to  produce  the  1,000  Ib.  in  8  hours  with  one 
firing,  space  for  100  Ib.  of  it  must  be  provided.  This 
being  a  West  Virginia  coal,  it  will  average  to  weigh 
about  50  Ib.  and  rarely  exceeding  53  Ib.  At  50  Ib.  to 

230 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

the  cubic  foot,  it  will  require  two  cubic  feet  of  vSpace  to 
hold  the  fuel  for  the  8-hour  run,  with  no  allowance  for 
waste  or  refiring. 

The  New  River  coal  is  listed  as  follows :  Moisture, 
0.85  per  cent ;  volatile  matter,  17.88  per  cent ;  fixed  car- 
bon, 77.64  per  cent;  ash,  3.36  per  cent;  heating  value  per 
pound  of  combustible,  15,800  B.  t.  u. 

The  ash  and  moisture  constitute  only  4.21  per  cent 
of  the  total  15,800  B.  t.  u.,  therefore  the  coal  as  it  enters 
the  furnace  has  a  theoretical  value  of  15,135  B.  t.  u.  Of 
this,  at  least  25  per  cent  is  lost,  leaving  9,837  B.  t.  u. 
for  steam,  or  a  trifle  over  10  Ib.  of  steam  to  the  pound 
of  coal  as  it  enters  the  furnace.  This  coal  then,  like  the 
Pocahontas,  will  require  a  fire-pot  space  about  one-quar- 
ter larger  than  strictly  anthracite  coal  will  require.  But 
the  instant  that  your  customer  indicates  that  he  pro- 
poses to  use  soft  coal  for  fuel  it  becomes  to  the  steam 
fitter  a  most  important  question  as  to  what  coal  he  means, 
and  he  cannot  intelligently  select  a  suitable  house-heating 
boiler  until  he  finds  out. 

As  we  have  seen,  if  he  means  to  use  a  high-grade 
semi-bituminous  coal  like  the  last  two  mentioned,  a  boiler 
capacity  increased  25  per  cent  will  answer.  But  if  he 
is  to  use  the  best  of  the  Ohio  coals  he  will  be  wise  to 
provide  for  an  increase  of  50  per  cent.  For  some  of 
the  western  coal  weighing  from  50  to  54  Ib.  per  cubic 
foot  the  available  value  of  the  coal  as  burned  in  the 
furnace  is  not  over  5  Ib.  of  steam  per  pound  of  the  fuel 
as  it  enters  the  furnace.  This  simply  means  that  if  that 
is  the  coal  to  be  used,  and  the  fitter  is  to  garantee  that 
the  boiler  he  is  to  furnish  will,  when  that  coal  is  used, 
maintain  steam  steadily  for  8,  9,  10  or  more  hours  with 
one  firing,  then  the  fitter  must  provide  a  holding  ca- 

231 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

pacity  for  the  boiler  at  least  double  that  which  would 
be  required  for  a  high-grade  hard  coal.  These  illus- 
trations show  the  need  of  the  manufacturer  clearly  stat- 
ing in  his  catalog  the  cubic  contents  of  the  fire-pot,  the 
pounds  of  hard  coal  he  considers  as  a  full  firing,  and  the 
proximate  net  value  per  pound  of  the  testing  coal  and 
the  hours  the  full  load  is  supposed  to  carry  its  rating. 

It  is  presumed  that  my  readers  will  understand  that 
the  various  illustrations  given  are  to  show  the  method 
by  which  a  person  can  arrive  at  a  fair  basis  of  judgment 
in  regard  to  the  space  that  will  be  certainly  required  to 
hold  the  amount  of  coal  called  for  according  to  the  con- 
stantly varying  demands  of  his  customers  as  to  hours  of 
firing,  the  use  of  different  kinds  of  coal,  and  the  like. 
The  factor  of  safety  that  should  be  used  in  each  case  has 
been  left  to  the  judgment  of  the  engineer  or  steam- 
fitter  who  is  to  garantee  the  job.  It  will  also,  I  trust 
be  fully  and  clearly  understood  that  in  all  cases  the  value 
of  a  pound  of  the  combustible  is  to  be  taken  instead  of 
the  value  of  the  pound  of  coil  as  given  in  many  catalogs. 

It  will  be  found  that  the  value  of  the  pound  of  com- 
bustible in  the  coal  from  a  given  section  of  country  will 
vary  but  slightly,  but  that  the  heating  value  of  individual 
coal-products  within  the  section  may  show  wide  differ- 
ences. Thus,  almost  the  entire  anthracite-coal-region  in 
Pennsylvania  produces  coal  which  shows  the  heating 
value  of  the  pound  of  combustible  to  be  14,900  B.  t.  u., 
but  mines  that  are  almost  side  by  side  may  show  de- 
cidedly sharp  and  important  differences  in  ash,  moisture 
and  volatile  matter.  Enough  to  make,  in  some  cases, 
the  fire-pot  of  one  make  of  boiler  the  point  of  selection 
as  against  another.  In  the  semi-bituminous  and  bitu- 


232 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

minous  coals  the  heating  value  per  pound  of  combustible 
is  found  to  be  remarkably  even  over  extended  areas. 

In  the  strictly  bituminous  coal  this  is  very  pronounced, 
and  the  steam-fitter  who  neglects  to  investigate  it  will, 
if  he  is  doing  any  considerable  heating  business,  surely 
get  into  trouble  at  times  on  account  of  that  neglect. 

For  instance,  the  Ohio  soft  coal  is  almost  certain  to 
show  a  heating  value  of  14,500  B.  t.  u.  per  pound  of 
combustible — that  is,  the  part  that  burns.  But  the  coal 
from  an  individual  mine  in  Ohio  might  show  that  1  Ib. 
of  its  coal,  as  it  came  from  the  dealer  ready  to  go  into 
the  furnace,  did  not  have  one-half  that  heating  value 
per  pound,  while  the  coal  from  a  mine  quite  near  it,  in 
the  same  condition,  might  show  that  it  had  20  or  25  per 
cent  more  heating  value  as  it  entered  the  furnace. 

This,  naturally,  means  that  the  steam-fitter  could,  if 
he  desired,  use  a  boiler  with  a  smaller  fire-pot  on  the  lat- 
ter job  than  would  be  safe  to  use  on  the  first,  although 
the  heating  value  of  the  pound  of  combustible  might  be 
the  same  for  each  coal. 

The  manufacturer  no  longer  makes  the  plans  or  gar- 
ant  ees  the  working  of  heating  jobs.  He  has  thrown  the 
burden  on  the  steam-Utter.  The  sooner  the  Utter  gets 
next  to  this  rating  and  fuel-proposition,  the  better  it  will 
be  for  him  individually  and  the  trade  collectively. 

Before  leaving  this  part  of  the  heating  question,  it 
should  be  stated  that  there  is  considerable  variation  in 
the  ash  of  coal,  according  to  its  size.  The  most  of  the 
analyses  used  for  the  illustrations  just  given  were  taken 
from  tables  published  by  the  Babcock  &  Wilcox  Co.  of 
New  York.  The  ash,  as  given,  is  evidently  the  result  of 
laboratory-conditions,  and  is  considerably  less  than  will 
actually  prevail  in  the  ordinary  run  of  practice.  But,  as 

233 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

has  been  said,  the  illustrations  are  given  that  the  reader 
may  understand  how  to  get  at  a  practical  working  basis 
from  which  to  start. 

In  regard  to  the  ash  developed  from  the  different  sizes 
of  a  lot  of  coal  taken  from  one  hard-coal  mine,  the  in- 
crease of  ash  as  the  size  became  smaller  was  considerable. 

From  the  Egg  size  the  ash  was 5.7     per  cent 

From  the  Stove  size  the  ash  was 10.00  per  cent 

From  the  Chestnut  size  the  ash  was 12.6     per  cent 

From  the  Pea  size  the  ash  was 14.6     per  cent 


234 


SECTION  XXXI. 


It  is  probable  that  there  is  no  great  difference  among 
the  various  tables  that  have  been  prepared  as  to  the  heat- 
ing value  in  B.  t.  u.  per  pound  of  combustible,  however 
much  they  may  vary  as  to  ash,  moisture,  fixed  carbon  and 
the  rest  These  variations  come  from  individual  or  spe- 
cial samples  usually.  What  the  fitter  needs  to  do  is  to 
get  from  the  dealers  in  the  territory  he  covers  the  com- 
plete analyses  of  the  coal  handled  therein.  From  these 
he  can  make  his  own  deductions  as  to  the  size  of  firepot 
that  will  be  required  for  different  coal,  always  starting 
from  the  value  given  in  B.  t.  u.  for  one  pound  of  com- 
bustible, and  deducting  for  ash  according  to  the  size  of 
coal  to  be  used.  Allowance  should  be  made  for  a  larger 
percentage  of  ash  in  small  sizes  than  for  the  large.  There 
should  always  be  a  liberal  factor  of  safety  added  to  the 
theoretical  space  as  determined  from  the  published 
analysis. 

In  the  matter  of  grates  for  boilers  there  is  no  reason 
why  any  of  the  grates  now  on  the  market  should  not  be 
taken,  if  the  firepot  and  other  important  things  are  suit- 
able to  the  work  to  be  done. 

The  matter  of  fire  or  heating  surface  is  not  by  any 
means  a  settled  question.  It  is  only  within  a  very  short 
time  that  any  real  data  on  the  value  of  the  various  items 
that  go  to  make  up  the  cast-iron  heating  boilers  has  been 
presented  by  independent  investigators.  In  fact,  the  only 
attempt  at  standardizing  seems  to  have  been  the  fixing 
of  the  relative  temperature  that  a  hot-water  boiler  should 

235 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

show,  as  the  correct  temperature  of  water  at  the  boiler, 
to  secure  a  rating  for  radiation  with  65  per  cent  increase 
over  that  given  for  the  same  construction  and  size  of 
steam-boiler  when  rated  for  steam  at  2  Ib.  at  the  boiler; 
and  the  rating  of  steam-boilers  as  carrying  2-lb.  pressure 
at  the  boiler. 

From  the  individual  tests  that  have  been  made  on 
nearly  every  type  of  cast-iron  heating  boilers,  it  is  quite 
well  demonstrated  that,  in  a  general  way,  the  same  law 
that  governs  the  value  of  heating  surface  in  tubular  boil- 
ers obtains  with  equal  force  when  considering  the  cast- 
iron  surface. 

But  the  roughness  of  the  flues,  in  the  cast-iron  con- 
struction, tends  to  develop  somewhat  larger  losses  be- 
cause of  the  quick  accumulation  of  soot  when  soft  coal 
is  used  as  fuel,  particularly  when  there  is  an  excess  of 
indirect  flue  surface.  The  tendency  of  this  surface  to 
collect  ash  when  anthracite  coal  is  used  seems  also  to  be 
more  pronounced  in  the  cast-iron  flue. 

The  tests  of  the  United  States  Geological  Survey  at  St. 
Louis,  Mo.,  and  of  the  Engineering  Experiment  Station 
of  the  University  of  Illinois  as  published  in  bulletin  No. 
366  of  U.  S.  G.  S.,  and  bulletin  No.  31,  of  the  University 
of  Illinois,  February,  1909,  are  practically  the  first  at- 
tempts, by  outside  engineers  of  high  standing,  to  test 
cast-iron  house-heating  boilers  on  a  somewhat  prolonged 
basis. 

These  tests  are  far  from  complete,  they  having  been 
made  to  determine  the  heating  value  of  various  fuels 
when  burned  in  the  cast-iron  house-heating  boiler.  The 
tests,  however,  disclose  incidentally  many  things  beside 
the  coal-value  that  are  of  importance  to  the  student  of 
the  heating  question  as  it  relates  to  the  house-heating 
problem. 

236 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

In  order  to  emphasize  what  has  already  been  said  in 
regard  to  the  general  lack  of  information  in  the  trade 
of  proper  data  upon  which  to  base  anything  like  an  accu- 
rate estimate  of  the  various  estimates  and  claims  of  the 
different  manufacturers,  I  quote  a  few  paragraphs  from 
the  bulletin  No.  31  of  the  University  of  Illinois,  dated 
Feb.  22,  1909. 

"Page  9. — On  account  of  the  small  amount  of  avail- 
able information  relative  to  a  satisfactory  method  for 
conducting  house-heating  boiler  tests,  one  of  the  prin- 
cipal purposes  in  conducting  these  tests  was  to  obtain 
information '  that  would  assist  in  developing  such  a 
method.  Fuel-tests  with  house-heating  boilers  will  of 
necessity  be  similar,  in  many  respects,  to  the  tests  made 
in  connection  with  power-boilers." 

''Page  11. — In  the  case  of  a  house-heating  boiler,  the 
question  relative  to  capacity  which  is  of  importance,  is 
how  many  square  feet  of  radiation  can  be  served  through 
comparatively  long  periods  of  time  without  attention, 
except  at  the  time  of  firing.  It  is  generally  desired  to 
know  how  many  square  feet  of  radiation  can  be  served 
through  a  period  of  from  six  to  eight  hours  without  at- 
tention during  that  time.  The  same  amount  of  fuel 
consumed  within  a  short  time  should  serve  more  radiat- 
ing surface  per  hour  than  when  burned  during  a  longer 
period  of  time.  The  one-hour  period  as  employed  in 
defining  a  horse-power,  and  as  used  in  rating  power- 
boilers,  is  not  satisfactory  for  comparative  purposes  in 
connection  with  house-heating  boiler-work.  In  this  kind 
of  work,  then,  in  order  that  information  relative  to 
capacity  may  have  the  greatest  usefulness,  it  should  be 
based  upon  the  evaporation  which  can  be  obtained  dur- 
ing a  period  of  from  six  to  eight  hours  without  atten- 

237 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

tion,  rather  than  upon  the  evaporation  obtained  in  one 
hour  with  whatever  attention  may  be  required.  Thus 
a  boiler  rated  at  1,000  sq.  ft.  should  be  capable  of  serv- 
ing that  amount  of  radiation  for  a  period  of  at  least  six 
hours  without  attention  during  that  time. 

"Page  12. — The  lack  of  a  satisfactory  method  of 
making  tests,  or  of  one  generally  accepted  as  such  was 
apparent.  Under  these  circumstances  it  was  deemed  ad- 
visable to  make  a  series  of  tests  according  to  the  Ameri- 
can Society  of  Mechanical  Engineers'  code  for  conduct- 
ing boiler-trials. 

"Page  14. — Societies  and  individuals  interested  in  this 
kind  of  work  have  from  time  to  time  reported  tests,  or 
discussed  methods  for  making  such  tests,  but  apparently 
without  making  definite  recommendations  that  have  been 
found  satisfactory  for  the  guidance  of  others,  or  that 
have  been  adopted  generally  enough  to  make  compari- 
sons possible  or  of  value.  The  number  of  tests  of  this 
kind  which  have  been  reported  is  surprisingly  small  as 
compared  with  the  number  of  tests  conducted  upon  pow- 
er-boilers. Probably  the  greatest  amount  of  work  in 
this  line  has  been  done  by  the  manufacturers  of  heating 
apparatus.  The  results  of  their  investigations  are,  how- 
ever, either  not  available,  or  are  applicable  to  particular 
makes." 

When  a  great  university,  as  recently  as  1909,  finds 
itself  utterly  unable  to  find,  even  among  the  house-heat- 
ing boiler-manufacturers  of  this  country,  a  method  of 
testing  cast-iron  heating  boilers  that  was  even  in  general 
use  among  themselves,  it  is  not  a  matter  of  great  sur- 
prise that  the  trade  have  up  to  the  present  time  no  gen- 
eral knowledge  of  the  important  points  that  they  should 
investigate  when  selecting  a  boiler.  The  time  has  now 

238 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

come,  however,  when  the  intelligent  engineer  and  steam- 
fitter  must,  in  justice  to  himself,  require  from  the  man- 
ufacturer the  dati  already  indicated  in  this  discussion, 
and  those  of  the  trade  who  are  in  the  fair  way  to  secure 
work  upon  a  larger  scale  than  residence-heating,  will 
naturally  require  considerable  data  in  addition. 

The  authorities  at  the  University  of  Illinois  were  jus- 
tified in  taking  the  code  of  the  A.  S.  M.  E.  fuel-tests 
for  power-boilers  as  the  guide  for  testing  cast-iron  boilers 
for  house-heating.  In  this  they  only  followed  the  exam- 
ple which  the  United  States  engineers  set  two  or  three 
years  previously  when  making  similar  tests  at  St.  Louis, 
Mo. 

Undoubtedly  one  of  the  chief  reasons  that  neither  of 
these  parties  found  any  satisfactory  rule  among  the 
cast-iron  boiler  manufacturers  of  the  country  was  the 
fact  that  nearly  every  boiler  on  the  market  from  1860 
to,  within  perhaps  ten  years,  or  1900,  which  was  made 
of  cast  iron,  was  some  sort  of  an  attempt  to  improve 
upon  the  Brayton  boiler ;  if  not  that,  then  the  Mills  or 
Gold,  in  the  vertical  sectional  type,  while  in  the  round 
horizontal  sectional  type,  the  boilers  without  an  excep- 
tion, were  either  direct  copies  of  foreign  boilers  without 
variation,  or  were  adaptations  of  the  upright  tubular 
boiler  of  the  high-pressure  type.  In  a  majority  of  cases 
the  manufacture  of  the  house-heating  boilers,  especially 
of  the  cast-iron  ones,  was  entered  into  by  some  foundry- 
man  who  saw  a  chance  to  increase  his  output  of  castings 
by  slightly  changing  his  patterns  from  those  of  some 
type  of  boiler  within  his  knowledge  that  was  giving  a 
fair  degree  of  satisfaction.  When  it  came  to  rating  the 
boiler,  the  foundryman,  with  characteristic  American 
confidence,  determined  that,  if  the  model  that  he  had 

239 


A    Practical    Manual    of    Steam    and    Hot- Water    Heating 

chosen  to  improve  upon  had  a  given  rating,  then  he  could 
safely  rate  his  production  at  the  same,  or  a  trifle  more, 
according  to  the  disposition  of  the  manufacturer. 

That  a  test  along  the  plain,  simple  lines  indicated  in 
tables  GZ  and  HZ,  pages  188  to  191,  was  made  prior  to 
1900  is  very  doubtful.  It  is  also  a  well-known  fact  that 
the  results  of  any  tests  made  by  any  of  the  boiler  manu- 
facturers who  cater  to  the  house-heating  trade  have  never 
been  given  out  in  a  form  that  would  enable  one  to  prompt- 
ly and  easily  determine  the  value  of  the  boiler  when  placed 
under  conditions  that  varied  from  those  under  which  the 
manufacturer  may  have  placed  his  boiler  and  secured 
what  he  was  pleased  to  call  its  rating.  Another  reason 
why  the  manufacturers  have  never  had  a  simple  straight- 
forward rule  for  the  testing  of  cast-iron  heating  boilers 
is  the  fact  already  stated  that  their  product  was  almost 
universally  sold  through  agencies.  As  a  rule,  only  one 
make  of  boiler  would  be  allowed  to  one  agent.  The 
manufacturer  usually  made  all  the  plans,  and  decided 
what  size  of  boiler  should  go  on  a  given  job.  There 
was  no  pinning  the  job  down  to  a  2-lb.  pressure-at-the- 
boiler  proposition.  If  a  job  would  not  give  out  heat 
enough  with  2-lb.  at  gage,  "fire  a  little  harder  and 
carry  more  pressure.  The  boiler  is  safe ;  burn  a  little 
fuel." 

There  is  not  ,a  man  in  the  trade  today  who  can  re- 
member back  ten  years  who  will  say  the  statement  just 
made  is  overdrawn.  But  when  the  trade  at  large  had 
become  somewhat  acquainted  with  the  general  practice 
of  steam-heating  for  residences,  and  the  public  were 
getting  particular  as  to  the  pressure  to  be  carried,  and 
the  amount  of  coal  to  be  burned,  the  manufacturers 
decided  that  the  modern  practice  had  developed  to  a 

240 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

point  where  steam- jobs  were  being  installed  at  times, 
and  probably  could  always  be  installed  in  residences,  and 
give  satisfaction  if  only  2-lb.  pressure  was  carried  at  the 
boiler. 

This  was  a  condition  of  economy  and  safety  for  the 
house-owner  much  to  be  desired.  It  would  also,  it  was 
thought,  simplify  boiler-ratings  by  bringing  all  boilers 
to  the  same  standard  of  2  Ib.  at  the  boiler  on  all  house- 
heating  boilers.  A  few  of  the  larger  producers  began 
to  rate  on  this  basis,  and  in  a  short  time  the  manufac- 
turers as  a  body  had  adopted  the  new  rating.  Practi- 
cally coincident  with  this  move,  came  the  almost  univer- 
sal cessation  on  the  part  of  the  large  producers  of  draw- 
ing plans  for,  or  the  laying  out  of  house-heating  jobs. 
These  steps  which  have  been  taken  by  the  boiler  manu- 
facturers within  a  very  short  period  of  time:  i.  e.,  do- 
ing away  with  the  agency  system,  stopping  plan- 
making,  and  adopting  a  definite  stated  pressure  as  a 
basis  of  rating:  have  had  the  effect  of  calling  the  at- 
tention of  the  United  States  Departmental  Officers 
and  engineers  to  the  question. 

The  first  thing  that  they  found  out  was,  that  there  was 
no  actual  standard  in  effect  which  governed  the  rating 
of  cast-iron  heating  boilers  such  as  were  used  in  resi- 
dences. The  next  thing  was,  that  of  those  manufactur- 
ers who  pretended  to  have  a  system  of  scientific  rating, 
no  two  of  them  were  alike,  or  agreed  in  full  with  each 
other  as  to  the  value  of  things  upon  which  they  did 
agree  as  being  important. 

Power-boiler  data,  at  the  time  of  the  Centennial  Ex- 
hibition at  Philadelphia,  was  found  to  be  in  this  same 
guess-work  sort  of  a  condition,  and  it  became  necessary 
to  formulate  a  code  for  testing  power-boilers.  This 

241 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

code,  with  certain  corrections  and  additions,  became 
what  is  now  known  as  the  Testing  Code  of  the  A.  S.  M. 
E.  for  Power  Boilers. 

There  is  no  great  exhibition  being  projected  to  require 
the  making  of  a  code  for  testing  house-heating  boilers, 
but  there  is  a  still  more  important  reason  that  requires 
such  a  code,  and  that  it  shall  be  settled  upon  quickly, 
and  correctly,  and  above  all  simply.  And  that  reason  is 
that,  with  the  taking  of  the  successive  steps  just  referred 
to,  the  steamfitter  and  the  engineer  have  had  all  the  bur- 
den of  performance  thrown  on  to  them.  The  manufac- 
turer is  out  from  that.  It  is  no  longer  a  question  for  a 
few  boiler  producers.  It  is  a  vital  matter  concerning 
the  pocket-book  of  every  house-heating  contractor  in  the 
entire  country. 


242 


SECTION  XXXII. 


I  do  not  claim  that  the  data  I  have  shown  as  absolutely 
necessary  to  be  given  out  by  every  boiler-producer,  in 
addition  to  the  little  that  they  now  do  give  out,  is  all  that 
should  be  covered  when  a  Testing  Code  for  House-heat- 
ing Boilers  is  finally  prepared.  Far  from  it.  But  I  do 
think  that  until  a  suitable  code,  that  all  can  agree  upon 
can  be  produced,  that  every  steam-fitter  and  engineer  is, 
for  his  own  protection,  in  duty  bound  to  find  out  for  him- 
self, in  some  way,  every  fact  covered  by  tables  GZ  and 
HZ  of  this  series.  And  in  addition,  as  much  data  in  re- 
gard to  the  firepot  size,  and  other  things  yet  to  be  taken 
up  fully,  as  he  may  require  for  his  personal  protection. 

In  the  matter  of  the  value  of  the  various  sections  of 
the  heating  surface  in  a  cast-iron  boiler,  the  boiler  men 
are  not,  as  yet,  a  unit.  A  very  exhaustive  series  of  tests 
covering  nearly  every  type  of  boiler  and  its  variations 
now  on  the  market  has  been  made  by  individuals,  and  to 
a  slight  extent  the  results  have  been  divulged,  and  the 
tests  are  quite  fully  in  accord  with  the  published  tests 
that  have  been  promulgated  as  to  the  value  of  the  heating 
surfaces  of  power-boilers. 

In  order  to  give  the  tests  that  have  been  made  on  the 
different  boilers  it  would  be  necessary  to  fill  a  space  equal 
to  more  than  that  used  in  the  average  magazine  in  10 
years  of  publication.  It  will  be  impossible  to  give  even  a 
summary  of  the  items  shown  by  Table  GZ  that  every 
boiler  catalog  should  give  in  detail  for  any  of  the  prom- 
inent cast-iron  lines  now  on  the  market,  for  the  reason 

243 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

that  there  is  not  one  single  line  that  is  not  full  of  varia- 
tions. There  is  not  a  boiler  catalog  covering  a  line  of 
cast-iron  boilers  that  is  fully  consistent  with  itself  all  the 
way  through.  The  stack-temperatures  are  found  to  vary 
all  the  way  from  the  200  deg.  F.  to  the  800  deg.  F.  in  tem- 
perature in  order  to  produce  the  catalog-rating  for  an 
eight-hour  run  on  some  lines,  while  on  another  line,  there 
may  not  be  a  stack-temperature  in  the  whole  list  that  will 
run  outside  of  the  recognized  points  of  greatest  economy 
for  boilers  of  this  class,  namely:  from  about  350  to  450 
deg.  F.  One  of  the  most  important  features  disclosed  in. 
my  personal  study  of  boiler  ratings  is  the  different  rates 
of  combustion  that  is  often  required  in  one  line  of  boilers 
to  secure  the  necessary  amount  of  steam  to  supply  the 
rating  for  any  definite  number  of  hours.  A  certain  line 
of  quite  popular  boilers  have  three  boilers  cataloged  in 
one  line  rated  to  carry  1,050,  1,250  and  1,400  sq.  ft.  of 
radiating  surface  on  a  certain  size  of  grate.  Another  line 
with  precisely  the  same  grate  and  about  the  same  fire 
surface  is  cataloged  at  850,  950  and  1,050  sq.  ft.  One 
other  popular  line  with  the  same  grate  surface  and  al- 
most the  same  heating  surface  is  cataloged  1,300,  1,425 
and  1,550  sq.  ft.  These  three  examples  are  not,  as  is 
sometimes  the  case,  all  cast  from  the  same  patterns,  ex- 
cept the  doors,  but  are  distinctly  different  in  the  arrange- 
ment of  the  sections.  In  each  case,  however,  when  tests 
are  made  of  the  three  there  is  developed  a  great  differ- 
ence in  the  stack-temperature  required  to  develop  from 
the  fuel  the  necessary  amount  of  steam  to  sustain  the 
catalog-rating  for  an  eight-hour  period.  These  are 
typical  boilers  selected  from  widely  separated  sections  of 
the  country.  Tests  on  these  show  that  there  is  no  change, 
whatever  in  the  grate  surface  or  size  of  fire-pot  in  order 

244 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

to  secure  the  increased  rating.  The  only  difference 
made  in  either  of  them  is  the  increasing  of  the  indirect 
heating  surface.  A  short  study  of  Tables  GZ,  HZ  and 
J  Z,  in  connection  with  these  ratings  should  enable  any 
one  to  see  what  was  done  to  produce  those  ratings  from 
the  same  amount  of  coal  held  by  the  same  firepot  on  the 
same  sized  grate.  It  is  hardly  necessary  to  state  that  the 
stack-temperature  on  the  three  ratings  varied  over  300 
deg.  between  the  highest  rating  and  the  lowest  if  an 
eight-hour  run  was  maintained  on  each  boiler. 

It  must  not  be  taken  from  the  foregoing  that  on  a 
round  type  of  boiler  that  two  or  three  different  ratings 
may  not  be  legitimately  given  to  a  given  size  of  grate 
and  firepot.  This  phase  of  the  question  has  been  ad- 
mirably stated  in  a  publication  recently  produced  for  pri- 
vate distribution,  as  follows :  "Boilers  that  have  a  mod- 
erate quantity  of  heating  surface  and  a  short  fire  travel 
will  operate  when  attached  to  a  flue  that  would  be  wholly 
inadequate  to  the  requirements  of  a  boiler  with  the  much- 
vaunted  long-fire  travel."  The  reason  for  this  is  that  the 
draft  in  the  chimney  flue  is  caused  by  the  difference  in 
the  temperature  of  the  column  of  air  in  the  chimney  and 
the  temperature  of  the  external  air;  and  the  boiler  with 
the  short-fire  travel  delivers  the  gases  to  the  chimney 
at  a  high  temperature,  which  lightens  the  column  of  air  in 
the  chimney,  causing  the  heavier  outside  air  to  take  its 
place,  thereby  creating  the  necessary  draft.  Because  of 
this  variation  in  the  chimney  intensity,  it  is  possible  to 
arrange  boilers  with  a  varying  number  of  sections  as  in 
the  round  type.  But  the  statement  that  there  must  be 
an  ideal  number  of  sections  which  should  be  placed  be- 
tween firepot  and  dome  of  all  round  boilers  is  mislead- 
ing, for  such  an  ideal  can  never  be  realized  owing  to  the 

245 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

wide  difference  in  the  intensity  of  chimney  drafts.  It  has 
been  demonstrated  by  actual  tests  that  the  addition  of  a 
limited  number  of  sections  above  the  firepot  increases 
proportionately  the  value  of  the  heating-  surface  in  the 
fire-pot  and  a  relative  increase  in  the  power  derived  from 
the  fuel,  thereby  allowing  a  proportionate  increase  in  the 
rating  of  the  boiler  (which  has  the  additional  sections) 
over  one  having  fewer  sections,  even  though  the  grate 
and  fuel  capacity  are  alike  in  both  boilers.  It  must  there- 
fore ahvays  res-t  with  the  heating  contractor  to  select  the 
boiler  which  will  suit  the  chimney  conditions." 

But  how  can  the  heating  contractor  intelligently  select 
from  any  catalog  now  in  use?  What  has  just  been 
quoted  in  regard  to  round  boilers,  is  equally  applicable  to 
every  kind  and  shape  of  vertical  sectional  boilers,  whether 
cast-iron  or  tubular. 

This  manual  was  commenced  with  a  discussion  of 
chimneys,  for  the  reason  that  the  chimney  and  its  quality 
of  draft  and  volume  absolutely  dominates  the  question 
as  to  the  exact  kind  of  a  boiler  best  to  put  in  for  most 
satisfactory  results. 

The  quality  of  the  draft  and  the  volume  of  it  will  first 
be  looked  at  to  determine  the  question  of  stack-tempera- 
ture that  can  be  selected  to  the  greatest  advantage  in  the 
matter  of  combustion.  The  range  may  be  anywhere  from 
250  deg.  F.  to  as  high  as  800,  or,  even  in  some  known 
cases,  over  1,000  deg.  F. 

The  usual  range,  however,  on  jobs  installed  in  places 
where  the  altitude  is  under  1,000  ft.  above  the  sea  level, 
for  house-heating  is  in  the  vicinity  of  350  to  450  deg.  F. 
in  the  stack  and,  with  the  exception  of  chimneys  that  de- 
velop most  unusual  draft  and  volume  combined,  the  cases 
where  a  boiler  requiring  a  higher  stack-temperature  than 

246 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

that  covered  by  those  figures  can  be  used  with  satisfac- 
tion to  steamfitter  and  owner  alike  are  quite  rare. 

It  will  not  require  a  very  long  hunt  on  the  part  of  the 
steamfitter,  however,  to  find  boilers  that  in  order  to  main- 
tain the  catalog-rating  will  have  to  show  at  least  700  to 
900  deg.  stack-temperature. 

Grant  that  we  have  considered  the  draft,  the  volume, 
and  the  general  condition  of  the  chimney;  the  kind  of 
coal  that  is  to  be  burned,  which  will  determine  the  B.  t.  u. 
available  per  pound ;  decided  as  to  the  number  of  hours 
that  the  job  is  to  run  without  attention ;  we  then  re- 
quire a  firepot  with  sufficient  cubic  contents  to  not  only 
hold  the  quantity  of  the  coal  that  is  to  be  used  in  the 
selected  time,  but  that  will  also  hold  a  good-sized  surplus 
in  order  to  provide  for  a  sufficient  amount  of  fuel  for  re- 
kindling. It  should  provide  for  an  hour  or  two  additional 
run  in  an  emergency,  or  when  the  outside  temperature 
is  several  degrees  below  the  zero  or  other  selected  winter 
temperature.  This  firepot  chosen,  the  question  of  the 
kind  and  amount  of  heating  surface  to  be  placed  above 
the  firepot  can  be  taken  into  the  account. 

As  has  been  stated,  this  is  a  point  over  which  there 
seems  to  be  an  honest  difference  of  opinion  among  the 
manufacturers,  and  among  the  trade  as  well. 

The  writer  of  this  series  has,  in  the  past,  been  favored 
with  the  views  of  nearly  all  the  most  prominent  produc- 
ers of  cast-iron  boilers  in  this  country,  and  has  had  the 
pleasure  of  meeting  some  of  the  largest  producers  of 
France,  England  and  Canada,  who  have  also  expressed 
their  views  on  this  question  of  heating  surface.  I  can 
only  say  that  as  the  net  result  of  all  these  interviews,  or 
talks,  that  the  cases  where  the  opinion  advanced  had 
been  based  upon  the  results  of  experiments  upon  a  large 

247 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

number  of  boilers  produced  by  other  manufacturers  than 
themselves,  were  very  rare.  And  in  these  few  cases  the 
experiments  were  in  only  two  or  three  instances  extended 
to  boiler  construction  that  differed  materially  from  that 
produced  by  the  investigator.  With  the  exception  of  a 
very  few,  the  position  taken  in  regard  to  the  matter  of 
heating  surfaces  can  be  summarized  in  the  statement 
that  all  surface  which  in  any  way  can  transmit  heat  from 
the  flame  or  the  gases  of  the  coal  to  the  water  in  the 
boiler  is  to  be  considered  as  heating  surface  in  that  boiler. 
In  only  an  occasional  instance  has  the  producer  suggested 
that  there  should  be  allowance  made  for  difference  in 
effectiveness  in  this  surface. 

Within  the  past  few  years  this  question  of  effective- 
ness of  surface  has  received  some  little  attention  from 
a  few  of  the  thinkers  connected  with  the  industry  of  heat- 
ing houses  with  steam  or  hot  water. 

That  the  matter  is  not  fully  appreciated  by  either  the 
architects,  or  the  trade  at  large,  is  evidenced  by  the  num- 
erous heating  specifications  that  come  to  the  trade  calling 
for  boilers  with  a  certain  size  of  grate  and  a  stated  gross 
amount  of  heating  surface,  but  not  one  word  as  to  the 
distribution  of  that  surface.  Not  a  word  as  to  whether 
it  is  to  be  placed  50  per  cent  direct  and  50  indirect,  or 
25  indirect  and  75  per  cent  direct,  or  in  some  other  com- 
bination. I  do  not  recall  this  ever  having  been  stated  in 
one  of  this  sort  of  specifications. 

It  is  not  necessary  to  discuss  the  question  as  to  whether 
the  surface  exposed  directly  to  the  flame  is  not  more 
valuable  than  that  not  so  exposed  and  usually  called  the 
flue-surface.  But,  it  is  of  importance,  to  carefully  ex- 
amine the  relative  value  of  the  two  in  the  common  house- 
heating  boiler. 

248 


SECTION  XXXIII. 


I  recently  saw  the  specifications  for  the  heating  of  a 
certain  building  by  steam.  They  were  drawn  by  an  archi- 
tect who  prides  himself  upon  the  entire  completeness  of 
his  specifications.  In  this  case  the  demand  was  for  the 
use  of  a  cast-iron  boiler  having  a  grate-area  of  not  less 
than  9.25  sq.  ft.  and  the  heating  surface  to  be  not  less 
than  220  sq.  ft.  The  intent  and  design  of  these  specifica- 
tions was,  probably,  to  secure  a  certain  boiler  which  he 
did  not  care  to  name  in  specific  terms.  But  it  developed 
that  there  were  a  number  of  cast-iron  boilers  that  had 
the  required  size  of  grate,  while  only  two  or  three  manu- 
facturers claimed  to  have  the  required  220  or  more  sq. 
ft.  of  heating  surface  attached  to  that  size  of  grate.  It 
soon  developed  that  no  two  of  the  manufacturers  who 
had  boilers  with  the  required  grate-area,  claimed  the  same 
amount  of  heating  surface  for  their  boilers.  The  strange 
thing  to  the  steam-fitter,  who  was  making  inquiry  from 
the  different  firms,  was  that  the  manufacturer,  who 
claimed  the  largest  amount  of  heating  surface  in  connec- 
tion with  the  correct  size  of  grate,  made  the  smallest 
claim  for  rating.  The  steam-fitter  and  the  architect  at 
once  jumped  to  the  conclusion  that  that  particular  boiler 
must  be,  by  all  means,  the  best  and  most  conservatively 
rated  of  any  of  the  product  of  manufacturers  of  whom 
they  had  made  inquiry.  This  particular  boiler  was  in- 
stalled. Because  of  its  supposed  conservative  rating,  the 
owner  of  the  building  decided  to  add  to  the  original 
proposition  two  rooms,  making  the  total  square  feet  of 
cast-iron  radiation  on  the  job  885  sq.  ft. ;  in  addition  to 

249 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

this  there  was  the  draft  of  the  piping,  a  portion  of  which 
was  well  covered. 

To  a  suggestion  that  was  made  to  the  fitter  that  pos- 
sibly he  was  rather  crowding  the  boiler,  and  that  when 
the  job  came  to  the  test  of  zero  weather  and  rough  wind 
that  he  would  have  trouble  in  store  for  himself,  he  re- 
olied,  with  great  confidence,  "that  he  was  not  a  bit  wor- 
ried on  that  score."  He  based  his  confidence  on  the  fol- 
lowing statistics. 

He  had  received  answers  to  his  questions  from  nine 
concerns.  Not  all  of  them  had  given  him  their  figures 
as  to  heating  surface.  But  all  had  replied  as  to  grate- 
surface,  and  the  difference  between  the  largest  and  small- 
est grate-surface  was  found  to  be  not  over  1-3  sq.  ft.  and 
the  concern  with  the  very  smallest  area  of  grate  had  a 
rating  among  the  largest.  The  boiler  they  had  selected 
had  a  grate-area  of  1,350  sq.  in. ;  claimed  heating  sur- 
face, 222  sq.  ft. ;  rating  claimed,  1,350  sq.  ft.  for  steam. 
The  list  of  ratings  run  as  follows :  1,350  sq.  ft,  1,350  sq. 
ft.,  1,450  sq.  ft.,  1,700  sq.  ft.,  1,800  sq.  ft.,  1,850  sq.  ft, 
1,950  sq.  ft.,  2,100  sq.  ft.,  2.150  sq.  ft. 

"We  have  found  an  eastern  boiler  that  has  a  grate 
8  sq.  in.  smaller  and  with  a  rating  of  1,350  sq.  ft. ;  they 
claim  to  have  two  square  feet  more  heating  surface,  but 
as  the  freight  would  be  more,  we  took  the  one  nearer 
home,  rated  for  1,350  sq.  ft/' 

"One  concern,  that  has  one  of  the  big  ratings,  wrote 
us  that  their  boiler  only  had  106  sq.  ft.  of  heating  sur- 
face, but  that  they  would  garantee  the  rating  they  put 
on  their  boiler.'' 

"If  a  concern  as  big  as  that  one  can  garantee  such  a 
rating  as  they  put  on  to  106  sq.  ft.  of  heating  surface,  we 
don't  think  we  need  to  fret  when  we  have  a  boiler  which 

250 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

a  first-class  concern  tells  us  in  writing  has  over  double 
that  amount  of  heating  surface  and  it  is  willing  to  gar- 
antee  that  the  boiler  is  correctly  rated." 

When  that  job  was  completed,  and  utterly  failed  to 
give  satisfaction,  the  surprise  of  the  architect  and  steam- 
fitting  firm  was  certainly  intense.  After  a  large  amount  of 
money,  relatively  speaking,  had  been  expended  in  the  at- 
tempt to  get  satisfactory  results,  the  producers  of  the 
boiler  finally  installed  another  of  their  boilers  which  car- 
ried a  catalog  rating  of  2,150  sq.  ft.  for  steam,  and  the 
job  worked  fairly  well.  If  the  architect  and  the  heating 
firm  had  fully  understood  the  value  of  the  position  of 
heating  surface,  they  would  have  examined  very  carefully 
the  position,  in  the  boiler,  of  all  of  that  222  sq.  ft.  of 
claimed  heating  surface.  It  is  not  for  the  writer  to  dis- 
pute the  correctness  of  the  manufacturers'  measure  of 
heating  surface,  but  I  can  say  that  in  order  to  secure  that 
amount  of  surface  he  had  to  measure  some  portions  of 
that  boiler  that  it  is  not  usual  to  consider  as  heating 
surface. 

The  experience  of  the  people  quoted  in  this  case  can 
hardly  be  considered  as  very  unusual.  Every  section  of 
the  country  can  produce  numerous  instances  of  a  similar 
nature,  but  perhaps  not  so  extreme.  There  were  errors 
in  the  piping  of  this  job  that  tended  to  demand  more  of 
the  boiler  than  is  usual  in  small  jobs  of  this  kind.  There 
is  no  claim  made  by  the  writer  that  this  boiler  was  in- 
correctly rated.  On  the  contrary,  its  rating  could  be  es- 
tablished for  a  very  short  run.  But  not  for  eight  hours. 
Nor  am  I  disposed  to  say  that  the  majority  of  the  steam- 
fitters  of  the  country  hold  the  same  view  that  was  held 
by  the  firm  I  have  quoted  in  regard  to  house-heating 


251 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

boiler  surface,  but  that  a  large  number  do  so  hold  is 
unquestioned. 

Some  of  the  highest  authorities  on  heating  and  venti- 
lation give  out  what  seems  to  be  substantially  the  same 
idea,  unless  they  are  very  carefully  read  and  understood. 
For  instance :  "The  International  Correspondence  Schools 
Plumbers'  and  Fitters'  Pocketbook,"  on  page  124,  states 
that  "In  ordinary  forms  of  house-heating  boilers,  from 
1,800  to  2,400  B.  t.  u.  are  absorbed  per  sq.  ft.  of  heating 
surface  per  hour,  and  since  1  sq.  ft.  of  direct  steam  radia- 
ting surface  requires  from  250  to  330  B.  t.  u.  per  hour, 
say  an  approximate  average  of  300  B.  t.  u.  per  hour,  it 
is  evident  that  1  sq.  ft.  of  boiler-heating  surface  will  gen- 
erate enough  steam  to  supply  from  6  to  10  ft.  of  radiating 
surface.  In  other  words,  a  vertical  sectional  boiler,  hav- 
ing 180  sq.  ft.  of  heating  surface,  will  supply  sufficient 
steam  for  1,080  to  1,800  sq.  ft.  of  direct  radiation,  in- 
cluding all  losses  due  to  condensation  in  the  transmission 
of  the  steam  through  the  supply-piping." 

Even  so  careful'a  writer  as  Prof.  Allen,  in  his  "Notes 
on  Heating  and  Ventilation,"  says:  "In  purchasing  a 
boiler  specify  the  number  of  square  feet  of  heating  sur- 
face the  boiler  should  contain." 

Both  of  these  authorities,  if  fully  and  carefully  read, 
make  these  extracts  clear,  but  read  as  most  of  the  trade 
look  through  a  book,  and  the  same  idea  is  absorbed  that 
was  presented  by  the  members  of  the  firm  I  quoted.  In 
fact,  in  the  course  of  a  series  of  talks  with  this  firm,  both 
of  the  quotations  just  given  were  presented  in  justifica- 
tion of  their  belief  that  the  boiler  with  222  sq.  ft.  of 
alleged  heating  surface  could  be  depended  upon  to  handle 
all  contingencies,  if  a  boiler  with  only  106  sq.  ft.  of  heat- 
ing surface  could  be  warranted  by  a  reputable  concern 

252 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

to  carry  a  big  percentage  more  surface  than  the  1,350 
sq.  ft.,  credited  to  the  220  sq.  ft.  of  claimed  heating  sur- 
face in  the  boiler  they  had  ordered  for  this  job. 

One  great  difficulty  in  the  study  of  the  house-heating 
boiler  is  that  nearly  all  the  books,  that  are  available  to 
the  average  steam-fitter,  fail  to  make  clear  the  difference 
in  the  matter  of  handling  the  ratings  of  the  ordinary  cast- 
iron  house-heating  boiler  and  the  power  boiler.  In  ad- 
dition to  this,  is  the  fact  that  but  very  few  competent 
writers  have  taken  up  this  side  of  the  question  since  the 
manufacturers  changed  the  manner  of  rating  so  that  cast- 
iron  boilers  for  steam  state  their  ratings  based  on  a  pres- 
sure not  to  exceed  2  Ib.  at  the  boiler. 

Another  reason  is,  that,  practically  all  those  who  have 
taken  up  the  heating  question,  have  taken  it  up  from  the 
standpoint  of  the  big  engineer  and  steam-fitter  and  the 
architect  of  the  big  building,  whose  calculations  are  "made 
to  accord  with  the  construction  of  the  tubular  boiler,  and 
who  only  considers  the  use  of  the  cast-iron  house-heat- 
ing boiler  at  long  intervals,  if  at  all. 

The  power-boiler  has,  for  the  past  60  years,  received 
about  all  the  attention  of  the  scientists  and  mechanics 
who  catered  to  large  work.  Even  as  late  as  1908,  two 
years  previous  to  the  present  writing,  William  J.  Bald- 
win, one  of  the  very  best  of  the  American  writers,  pub- 
lished the  16th  edition  of  his  work  on  heating,  having 
revised  the  former  editions  and  brought  the  16th  to  "har- 
monize with  modern  practice."  He  says  in  the  preface 
to  this  last  edition  that  "So  far  as  the  (1st)  work  related 
to  the  principles  of  steam-heating,  where  the  water  of 
condensation  is  returned  by  gravitation  to  the  boiler, 
there  could  be  little  change  in  the  book.  To  bring  it 
down  to  modern  practice  in  the  use  of  steam  by  other 

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A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

methods,  a  general  revision  was  necessary.  Therefore 
the  whole  former  book  is  superseded  by  one  whose  date 
and  practice  harmonize.  I  therefore  endeavor  to  give 
some  facts  relating  to  the  principles  of  modern  steam- 
fitting,  which,  since  the  writing  of  my  first  book  (1878) 
has  risen  to  the  dignity  of  a  branch  of  engineering  sci- 
ence that  may  be  known  as  domestic  engineering,  and 
which  includes  substantially  all  that  goes  to  make  up  the 
engineering  plant  of  a  modern  city  building,  except  the 
electric  light  and  elevator  system,  which  do  not  properly 
belong  to  the  subject." 

I  have  quoted  thus  freely  from  Mr.  Baldwin's  preface 
to  his  new  book  for  two  reasons.  First,  because  Mr. 
Baldwin  was  a  good  engineer  when  he  wrote  his  first 
book  in  1878  and  is  a  better  one  in  1908. 

Second,  because  Mr.  Baldwin  in  the  preface  quoted, 
and  in  the  text  of  his  most  excellent  book,  most  fully 
substantiates  the  fact  that  the  competent  writers  have 
not  taken  up  carefully  this  matter  of  cast-iron  boiler- 
ratings  and  their  construction,  and  the  relation  of  the 
heating  surface,  to  the  ratings  as  now  given  out  in  the 
catalogs  of  cast-iron  steam  and  water  boilers. 

As  a  matter  of  fact,  even  in  this  revised  edition  of 
1908,  Mr.  Baldwin  in  giving  the  requirements  for  house- 
heating  boilers  confines  himself  entirely  to  the  detail  of 
tubular  boilers,  and  simply  gives  the  names  and  descrip- 
tion in  the  briefest  possible  terms  of  8  or  9  of  the  most 
widely  known  cast-iron  boilers. 

The  20,000  men  in  this  country  who  do  house-heating, 
using  cast-iron  boilers  almost  entirely  in  their  work,  can 
get  much  that  is  of  the  utmost  importance  to  them  from 
this,  and  other  recent  books  by  men  of  experience.  So 
far  as  I  have  observed,  however,  there  has  as  yet  been 

254 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

no  detailed  information  that  will  give  them  the  practical 
information  in  regard  to  cast-iron  boilers,  such  as  they 
use  in  their  work,  that  is  given  in  all  the  books  in  regard 
to  the  power-boilers,  which  most  of  them  seldom  are 
called  upon  to  place. 

To  make  the  attempt  to  give  this  information  to  this 
army  of  workers,  as  fully  and  clearly  as  possible,  is  the 
object  of  these  essays. 

In  regard  to  this  matter  of  cast-iron  boiler-surface,  it 
should  be  stated  at  the  very  outset  that  the  last  word 
which  shall  fully  determine  the  exact  law  of  the  trans- 
mission of  heat  to  water  through  metal  plates  has  not 
yet  been  spoken. 

Scientists  have  made  many  experiments  which  seem  to 
point  toward  the  truth  of  the  statement  that  'The  evap- 
orative action  of  different  portions  of  the  heating  sur- 
face of  a  steam-boiler  point  to  the  general  law  that  the 
quantity  of  heat  transmission  per  degree  of  difference  of 
temperature  is  practically  uniform  for  various  differences 
of  temperature,"  but  there  is  much  to  be  ascertained  in 
regard  to  the  question  before  laboratory  exactness  as  to 
the  law  can  be  stated. 

For  the  practical  purpose  of  deciding  as  to  the  heating 
value  of  surface  in  a  cast-iron  boiler,  the  assumption  that 
the  evaporative  action  is  uniform  per  degree  of  differ- 
ence is  a  safe  base  from  which  to  make  calculations. 
At  this  point  we  come  up  against  an  almost  blank  wall 
so  far  as  positive  -claims  of  the  boiler-makers  are  con- 
cerned. If  any  of  them  have  published  to  the  trade  in 
general  anything  on  this  point,  it  has  not  been  seen  by 
the  writer  of  this  book. 

There  have  been  some  statements,  made  privately,  giv- 
ing the  results  of  tests  made  on  a  certain  line  of  boilers 

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A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

that  would  seem  to  indicate  that  the  law,  as  generally 
accepted,  may  be  considered  correct  as  to  the  transmis- 
sion, but  that,  in  so  far  as  cast-iron  boilers  are  concerned, 
there  is  a  larger  loss  in  what  may  be  termed  the  un- 
accounted-for units  than  is  usual  with  brick-set  tubular 
boilers. 


256 


SECTION  XXXIV. 


Before  taking  up  this  important  matter  of  position  of 
heating  surface  in  detail,  it  may  be  well  to  quote  from 
two  or  three  of  the  best  known  authorities  on  heating 
boilers. 

W.  J.  Baldwin  in  his  newi  book  says,  on  page  57 :  "A 
square  foot  of  surface  in  a  firebox  of  ordinary  construc- 
tion has  ^y-2.  to  4  times  the  value  of  the  same  area  of  aver- 
age tube  surface,  but  they  should  not  convey  the  idea 
that  by  increasing  surface  near  or  in  the  firebox  and  de- 
creasing the  tube  surface  near  or  in  the  direction  of  the 
chimney  in  a  three-fold  proportion  to  the  increase  in  the 
firepot,  that  they  can  evaporate  as  much  water  with  the 
increased  surfaces.  Makers  of  cast-iron  boilers  often 
make  this  claim.  When  a  firebox  or  furnace  is  large 
enough  for  proper  combustion,  its  surface  is  then  receiv- 
ing all  the  radiant,  heat  there  is.  By  increasing  the  sur- 
face directly  exposed  to  the  action  of  the  fire  (beyond 
the  required  chamber  for  combustion)  it  will  be  neces- 
sary to  have  the  surface  of  the  firebox  as  a  whole  more 
remote  from  the  fire,  and  the  radiant  heat  from  any 
source  has  its  effect  decreased  directly  as  the  surface 
ivhich  absorbs  it." 

Professor  Carpenter,  in  his  book  on  "Heating  and  Ven 
tilating,"  says:  "That  part  of  the  heating  surface  which 
is  close  to  the  fire  and  receives  directly  the  radiant  heat 
is  mutfh  more  effective  than  that  which  is  heated  by  con- 
tact with  hot  gases  only;  but  it  will  be  found  that  con- 
siderable indirect  heating  surface  will  in  every  case  be 

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A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

required  in  order  to  prevent  excessive  waste  of  heat  in 
the  chimney." 

Alfred  G.  King,  in  his  book,  "Practical  Steam  and  Hot 
Water  Heating  and  Ventilation,"  1908  edition,  says  :  "Di- 
rect-surface is  more  effective  than  flue-surface,  the  pro- 
portion being  about  3  to  1.  It  would  seem,  therefore,  that 
the  boiler  presenting  the  most  direct  surface  to  the  action 
of  the  fire  would  be  the  most  effective.  This  is  true  only 
in  a  measure,  as  a  boiler  may  have  a  large  amount  of 
direct  surface  and  yet  have  so  little  flue-surface,  or  dis- 
tance of  fire  travel,  that  the  heat  from  the  gases  of  com- 
bustion is  not  thoroughly  extracted  before  passing  into 
the  chimney,  and  a  large  number  of  heat-units  from  the 
fuel  consumed  is  therefore  wasted." 

Nearly  every  book  of  modern  date,  which  takes  up 
this  boiler  question,  will  have  a  general  statement  of  the 
tenor  of  those  just  quoted.  But  these  are  as  direct  and 
definite  as  any  I  have  noticed  in  any  of  the  recent  publi- 
cations. Probably  no  reader  of  this  series  of  articles  will 
dispute  the  correctness  of  the  general  statement,  but  I 
think  it  quite  probable  that  there  are  numbers  of  my 
readers  who,  like  the  man  from  Missouri,  desire  to  be 
shown  more  definitely  the  real  value  of  these  surfaces 
and  the  bearing  that  they  really  have  on  the  capacity 
of  a  boiler. 

But,  as  in  many  other  things  in  the  heating  business, 
they  find  themselves  left  by  most  writers  to  guess  as  best 
they  can  what  the  starting  point  in  the  transmission  of 
heat  through  the  fire-pot  heating  surface  may  be  and  then 
to  guess  again  as  to  whether  the  flue-surface  in  a  given 
boiler  is  worth  2*/2,  or  3,  or  4,  or  some  other  times  less 
than  the  fire-pot  surface.  It  is  rather  strange  that  this 
most  important  feature  of  the  cast-iron  boiler  has  been 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

so  universally  side-stepped  by  all  of  the  later  and  best 
writers.  That  something  definite  is  needed  is  apparent 
to  every  one.  As  we  proceed  to  discuss  this  feature  of 
the  cast-iron  heating  boiler,  the  positive  necessity  of  a 
precise  statement  from  every  boiler-manufacturer  as  to 
the  exact  number  of  square  feet  of  each  kind  of  heating 
surface  in  his  various  boilers  in  his  catalogs  will  be  so 
clear  that  no  careful  buyer  will  again  purchase  a  boiler 
until  such  data  is  not  only  furnished,  but  the  correctness 
of  the  figures  garanteed.  There  are  today  but  few  of 
the  boilers  which  are  offered  for  sale  that  have  the  ac- 
tual surface  claimed  by  the  manufacturers.  I  do  not 
recall  one  single  instance  of  a  catalog  that  gives  what 
the  manufacturer  claims  to  be  the  direct  and  the  indirect 
surface  for  heating  in  his  product. 

Now  that  the  burden  of  selection  and  garantee  of  the 
boiler  has  been  thrown  onto  the  steam-fitter  and  the 
engineer  by  the  manufacturer,  the  discussion  that  follows 
will  clearly  show,  I  believe,  that  not  one  single  manu- 
facturer of  cast-iron  boilers  at  this  time  gives  out  to  the 
public  the  most  vital  point  of  information  in  regard  to 
his  product  that  he  has  to  give.  The  reason  will  also 
be  made  somewhat  obvious  by  an  illustration  from  an 
actual  transaction.  A  clear  and  practical  rule  for  getting 
at  the  real  value  of  these  surfaces  will  also  be  developed 
by  the  discussion. 

There  are  but  few  reliable  records  of  the  value  of 
boiler-surfaces  in  this  matter  of  transmission,  through 
the  heating  surfaces,  of  the  heat  to  the  water  in  the 
boiler,  and  expressed  in  B.  t.  u.  per  degree  of  difference 
per  square  foot  of  surface  per  hour. 

The  largest  transmission  per  square  foot  per  hour  men- 
tioned by  any  reliable  author  is  that  given  by  Prof.  Kent 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

in  his  manual  for  engineers,  1910  edition.  It  is  there 
stated  that  in  a  locomotive-boiler,  where  radiant  heat  was 
brought  into  play,  that  17  units  of  heat  were  transmit- 
ted through  the  plates  of  the  fire-box  per  degree  of 
difference  of  temperature  per  square  foot  per  hour. 

It  should  be  remembered  that  there  is  a  vast  differ- 
ence between  the  transmission  of  heat  through  iron  to 
water  and  the  transmission  of  heat  from  steam  or  water 
through  iron  surface  to  water,  or  the  transmission  of 
heat  from  steam  or  water  to  air  through  iron  surfaces. 

TABLE  KZ. 


Temp,  of  water  in  boiler,  Degs. 

Fahr 200  200  200  200  200 

Temp,  of  gases  in  boiler,  Degs. 

Fahr 1200  1100  1000  900  800 

Degrees  of  difference  in  Temp.  1000       900       800       700       600 

B.  t.  u.  transmitted  per  sq.  ft. 
surface  per  degree  of  differ- 
ence per  sq.  ft.  per  hour 10  9  8  7  6 

Total  B.  t.  u.  transmitted  per  sq. 

ft.  per  hour 10000  8100  6400  4900  3600 

Sq.  ft.  of  steam-radiation  carried 

by  1  sq.  ft.  heating  surface.  ..41.66  33.75  26.66  20.41  15.00 


From  the  heated  water  on  one  side  of  an  iron  plate 
there  may  be  transmitted  400  or  even  600  B.  t.  u.  per 
sq.  ft.  of  surface,  per  degree  of  difference,  to  colder 
water  on  the  other  side  of  the  plate.  But  the  quantity 
of  heat  that  the  water  will  transmit  to  air  through  the 
same  plate  will  be  from  less  than  one  unit  to  possibly 
five  under  the  most  favorable  conditions. 

For  instance,  the  average  house-heating  radiator  rarely 
transmits  2  B.  t.  it.  per  degree  of  difference  of  tempera- 

260 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

ture  between  the  water  or  steam  in  the  radiator  and 
the  air  of  the  room.  This  point  must  not  be  overlooked 
when  considering  the  manufacturer's  claim  as  to  the 
heating  surface  in  a  given  boiler. 

From  all  the  available  data  at  my  command  I  am  per- 
suaded that  the  cast-iron  heating  boilers  now  on  the 
market  are  usually  tested  when  the  fire-pot  gases  approxi- 
mate a  temperature  of  1,200  deg.  F.  Some  of  them,  be- 
cause of  the  grouping  of  their  surfaces,  producing  un- 
usual flue-surfaces,  have  to  secure  a  higher  temperature 

TABLE   KZ. 


200    200   200   200   200   200   200   200   200   200 

700    600   500   400   350   300   250   240   230   220 
500    400   350   300   150   100    50    40    30    20 

5  4  3  2  1.5  1  0.5  0.4  0.3  0.2 
2500  1600  900  400  225  100  25  16  9  4 
10.41  6.60  3.75  1.66  .938  .416  .105  .066  .038  .017 

than  that  in  order  to  develop  their  catalog-rating;  oth- 
ers, because  of  deficient  flue-surface,  can  develop  their 
rating  at  a  somewhat  lower  temperature  than  1,200  deg. 
The  general  law  that  the  heat  transmitted  per  degree 
of  difference  of  temperature  is  practically  uniform  for 
the  various  temperatures  reached  in  testing  boilers,  when 
applied  to  the  house-heating  boiler-surfaces,  throws  a 
flood  of  light  on  to  this  rating  question,  and,  if  intelli- 
gently applied,  will  go  far  to  prove  the  correctness  of 

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A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

my  statement  that  there  is  no  single  line  of  boilers  in  the 
market  today  that  can  furnish  the  absolutely  best  boiler 
to  put  on  every  job. 

Apply  the  law  to  the  two  boilers  already  mentioned  in 
this  discussion. 

The  manufacturers  of  each  made  claim  as  to  heating 
surface  as  follows,  the  data  having  been  obtained  only 
after  considerable  correspondence.  One  claimed  220  sq. 
ft.  of  total  heating  surface,  divided  as  follows:  Direct 
surface,  30  sq.  ft. ;  indirect  surface,  190  sq.  ft. ;  stack-tem- 
perature when  tested  about  220  deg.,  catalog  rating,  1,350 
sq.  ft.  steam.  This  boiler  we  will  call  Boiler  A.  The 
other,  or  Boiler  B,  claimed  to  have  106  sq.  ft.  of  total 
heating  surface,  divided  into  43  sq.  ft.  direct  surface,  and 
63  sq.  ft.  indirect  surface.  Stack-temperature,  when 
tested,  about  400  deg.  Catalog-rating,  1,950  sq.  ft.,  steam 
radiation. 

While  experiment  has  shown  that  a  locomotive-boiler- 
plate, in  the  fire-box,  transmitted  17  B.  t.  u.  per  degree 
of  difference  of  temperature,  the  tests  on  cast-iron  house- 
heating  boilers  show  that,  at  a  temperature  of  1,200  deg. 
in  the  fire-box,  and  with  the  circulating  water  in  the 
boiler  at  about  200  deg.,  that  there  is  transmitted  10 
B.  t.  u.  per  degree  of  difference  of  temperature.  This 
difference  being  approximately  1,000  deg.,  we  can  con- 
clude that  there  is  one  unit  of  heat  transmitted  for  each 
100  deg.  of  difference.  This  conclusion  is  verified  by  the 
results  obtained  from  a  multitude  of  tests.  It  is  an  easy 
matter  to  construct  a  table  from  this  data  of  the  B.  t.  u. 
transmitted  per  degree  of  difference  of  temperature  be- 
tween the  heated  gases  and  the  water  over  the  fire-pot 
surface,  and  the  temperature  of  the  flue-gases  and  the 
water  as  it  circulated  in  the  boiler. 

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A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

The  ratio  of  the  heat  in  the  fire-pot  section  and  the 
beginning  of  the  flue-surface  is  as  12  to  8.  If  the  fire- 
pot  gases  have  a  temperature  of  1,200  deg.,  the  begin- 
ning of  the  flue-surface  will  show  a  temperature  of  about 
800  deg.  The  difference  between  the  water  in  the  boiler, 
as  it  circulates,  and  the  temperature  of  the  gases,  is  there- 
fore 1,000  deg.  for  the  fire-surface,  and  600  deg.  at  the 
beginning  of  the  flue-surface. 

The  person  who  desires  to  make  an  intelligent  choice 
of  a  boiler  for  a  given  condition  will  find  table  K  Z  one 
of  the  highest  importance  to  him.  For  convenience  of 
demonstration  I  have  taken  the  temperature  of  the  water, 
as  it  circulates,  to  be  200  deg.  in  the  boiler,  but  any 
other  temperature  can  be  taken  as  well,  as  the  relative 
values  will  remain  the  same.  That  is  to  say,  those  within 
the  range  of  house-heating  temperatures. 

The  column  that  shows  the  number  of  square  feet  of 
steam-radiation  condensing  Y^  Ib.  steam  per  hour  that 
each  square  foot  of  the  heating  surface  will  carry,  is 
especially  startling,  when  considered  in  the  light  that 
many  manufacturers  have  desired  us  to  look  at  their 
boilers,  viz.,  the  great  amount  of  flue-surface  that  they 
have  contrived  to  get  into  their  product. 


26:* 


SECTION  XXXV. 


-In  case  radiation  of  a  greater  condensing  capacity  is  to 
be  used,  or  that  of  a  smaller  value,  the  needed  correction 
can  easily  be  made  by  dividing  the  total  B.  t.  u.  transmit- 
ted per  square  foot  per  hour  from  the  required  heating 
surface,  by  the  number  of  B.  t.  u.  that  the  required  radi- 
ating surface  will  condense  per  square  foot  per  hour. 
Thus,  if  a  pipe  condensing  3  B.  t.  u.  per  degree  of  dif- 
erence  was  to  be  used  in  a  room  which  is  to  be  kept  at 
70  deg.  F.,  the  total  heat  transmitted  by  the  boiler  heat- 
ing surface  at  a  given  temperature  would  be  divided  by 
450  B.  t.  u.  in  order  to  find  the  number  of  square  feet 
of  surface  that  one  square  foot  of  the  heating  surface 
would  carry.  As  the  boilers  are  all  rated  at  2-lb.  pressure 
at  the  boiler,  the  utmost  temperature  that  the  steam  could 
have  in  the  radiators  would  be  220  deg.  Then  220  —  70 
=  150  deg.  diff.,  150  X  3  =  450  B.  t.  u.  If  this  radi- 
ation was  used,  the  fire-pot  surface  would  carry  22  sq.  ft. ; 
the  flue-surface  according  to  its  value.  The  absurdity  of 
the  popular  notion  that  a  very  low  stack-temperature  is 
needed  for  best  results  is  made  quite  manifest  by  this 
table. 

Now  let  us  examine  the  boilers  A  and  B  in  the  light 
of  facts,  instead  of  guess-work,  and  perhaps  we  can  find 
out  why  the  boiler. with  the  big  heating  surface  fell  down 
in  performance  when  put  to  the  test  of  severe  weather. 

Boiler  A  was  claimed  to  have  220  sq.  ft.  of  heating 
surface,  30  ft.  of  which  were  in  the  fire-pot.  Taking  a 
fire-pot  temperature  of  1,200  deg.  as  the  probable  test- 

264 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

ing  temperature,  we  find  by  Table  K  Z  that  a  square 
foot  of  heating  surface  will  transmit  10,000  B.  t.  u.  per 
hour.  Then,  10,000  X  30  =  300,000  B.  t.  u.  that  will  be 
transmitted  by  the  direct  surface.  The  beginning  of  the 
flue-surface  will  have  a  temperature  of  800  deg. ;  the 
temperature  of  the  water,  as  it  circulates,  is  200  deg., 
the  difference  being  600  deg.  The  stack-temperature  they 
claimed  to  be  220  deg.  at  the  test.  Therefore,  the  differ- 
ence at  that  point  would  be  20  deg.  and  the  average 
temperature  of  the  flue-gases  would  be  510  deg.  With  the 
water,  as  it  circulates,  at  200  deg.,  the  average  difference 
of  the  water-temperature  in  the  boiler  and  the  average 
flue-temperature  will  be  310  deg.  This  means  that  the 
surface  will  transmit  on  an  average  3.1  B.  t.  u.  per  de- 
gree of  difference,  or  a  total  of  182,500  B.  t.  u.  The  total 
transmitted  then  is  482,500  B.  t.  u.  It  will  not  do  to 
figure  on  the  whole  of  this  reaching  the  radiators,  be- 
cause many  experiments  have  demonstrated  that  there  is 
always  a  loss  not  accounted  for  at  the  radiators.  This 
loss  may  be  fairly  fixed  at  about  15  per  cent.  Deduct- 
ing this  loss,  which  cannot  reach  the  radiators  or  pip- 
ing, and  the  total  number  of  heat-units  that  can  be  relied 
upon  to  reach  the  radiators  and  piping  attached  to  this 
boiler  is  410,125  B.  t.  u.  As  one  foot  of  standard  cast- 
iron  radiation  has  been  generally  accepted  by  the  manu- 
facturers of  cast-iron  boilers  to  emit  240  B.  t.  u.  under 
the  usual  conditions  of  house-heating,  we  divide  the  410,- 
125  by  240,  and  find  that  the  gross  capacity  of  the  boiler 
is  for  1,708  sq.  ft.  cast-iron  radiators. 

The  producer  of  this  boiler  called  particular  attention 
to  his  claim  that  his  catalog-rating  was  only  80  per  cent 
of  the  gross  capacity.  In  order,  then,  to  test  the  catalog- 
rating  we  must  deduct  the  factor  of  safety  that  he  claims. 

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The  net  capacity  of  the  boiler  for  catalog-purposes  is  in 
round  numbers,  1,366  sq.  ft.  This  being  16  sq.  ft.  more 
than  the  catalog  calls  for,  we  must  conclude  that  the 
rating  is  correct  and  conservative,  under  the  conditions 
named. 

We  will  now  examine  boiler  B  in  the  same  manner. 
This  boiler  is  claimed  by  the  manufacturer  to  have  the 
same  size  of  grate  as  boiler  A.  The  claim  for  total 
heating  surface,  however,  is  for  an  amount  less  than  one- 
half  that  claimed  for  boiler  A  and  very  differently  dis- 
tributed. Boiler  B  is  claimed  to  have  106  sq.  ft.  of 
total  heating  surface ;  63  sq.  ft.  in  the  fire-pot  surface,  as 
direct  surface;  and  43  sq.  ft.  of  flue-surface,  which  is 
indirect  surface.  Using  the  same  temperatures  that  were 
taken  by  boiler  A,  we  arrive  at  the  following  data :  63 
sq.  ft.  transmitting  10,000  B.  t.  u.  per  ft.  yields  630,000 
B.  t.  u.  The  stack-temperature  established  by  the  pro- 
ducer, of  boiler  B,  was  400  deg.  Deduct  the  tempera- 
ture of  the  water,  as  it  circulates,  or  200  deg.,  and  we 
have  the  temperature-difference  at  the  stack-end  of  the 
flue-surface.  The  fire-pot  end  of  the  flue  is,  of  course, 
the  same  as  in  boiler  A,  or  800  deg.,  the  difference,  600 
deg.,  being  the  same  as  in  boiler  A.  The  average  differ- 
ence of  the  temperature  in  boiler  B  flue-surface  is  400 
deg.,  yielding  4  B.  t.  u.  per  square  foot  of  surface  per 
degree  of  difference.  The  flue-surface  of  boiler  B  yields 
43  X  4  X  400  =  68,800  B.  t.  u.  per  hour.  The  total 
B.  t.  u.  transmitted  =  698,800.  The  same  loss,  or  un- 
accounted-for units  by  pipe  and  radiators,  must  always 
be  deducted,  viz.,  15  per  cent.  There  are  then  59,980 
B.  t.  u.  available  as  the  gross  capacity  of  the  boiler  B. 
We  must  take  the  same  factor  of  safety  that  we  used  for 
boiler  A,  or  20  per  cent  of  the  gross,  leaving  80  per  cent 

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A    Practical    Manual    of    Steam    and    Hot- Water    Heating 

of  the  2,478  sq.  ft.  gross  capacity  for  the  catalog-rating. 
The  catalog-rating  of  boiler  B  is  1,950  sq.  ft.  Then,  80 
per  cent  of  2,478  is  1,982.  It  is  evident  that  boiler  B  is 
even  more  conservatively  rated  than  the  boiler  A,  when 
the  fire-pot  gases  are  at  1,200  deg.  F. 

It  is  certain  that  no  house-owner  will  maintain  a  per- 
manent temperature  of  1,200  deg.  in  the  fire-pot  of  his 
heating  boiler,  therefore  an  examination  of  these  two 
boilers  at  a  lower  fire-pot  temperature  may  be  of  interest. 

Suppose  we  take  for  the  trial  a  rather  moderate  fire- 
pot  temperature  of  about  900  deg.  The  temperature  of 
the  water,  as  it  circulates,  must  remain  the  same,  or  at 
about  200  deg.  The  beginning  of  the  flue-surface  will 
be  at  about  2-3  of  the  fire-pot  temperature,  or  at  600 
deg.  The  stack-temperature  of  each  boiler,  we  will  as- 
sume, to  be  in  perfect  proportion  with  the  fire-pot  gases 
when  at  1,200  deg.,  or  165  deg.  for  boiler  A  and  300  deg. 
for  boiler  B.  The  difference  will  be,  for  boiler  A,  700 
deg.  for  the  fire-pot  direct  surface  and  400  for  the  fire- 
box end  of  the  flue-surface;  but,  at  the  stack-end  of 
the  flue,  the  temperature  will  be  below  that  of  the  water 
as  it  circulates.  The  average  temperature  of  the  flue- 
surface  of  the  boiler  A,  because  of  this,  will  not  be  above 
382  deg.,  from  which  must.be  deducted  the  temperature 
of  the  water  as  it  circulates,  or  200  deg.  So  that  the 
average  difference  will  be  182  deg. 

At  this  temperature,  one  average  square  foot  of  boiler 
A's  flue-surface  transmits  1.82  B.  t.  u.  per  degree  of  dif- 
ference per  hour.  Applying  this  data  to  boiler  A,  we 
have  the  following:  The  30  sq.  ft.  of  direct  surface  at 
700  deg.  difference  will  transmit  147,000  B.  t.  u.  (4,900 
X  30  =  147,000— See  Table  K  Z).  The  190  sq.  ft.  of 
flue-surface  will  transmit  62,935  B.  t.  u.  (1.82  X  182  = 

267 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

331.2-1;  331.24  X  190  =  62,935).  The  total  transmission 
is  therefore  209,943  B.  t.  u.  per  hour.  Fifteen  per  cent 
of  this  will  not  be  accounted  for  through  the  piping  and 
radiators,  therefore  we  have  for  actual  use  178,451  B. 
t.  u.  As  each  square  foot  of  radiator  is  to  emit  240  B. 
t.  u.  per  square  foot  per  hour,  the  boiler  can  only  carry 
743  sq.  ft.  gross,  when  a  moderate  fire  is  used. 

Boiler  B  under  the  same  conditions  will  show  results 
from  its  surface  as  follows :  The  63  sq.  ft.  direct  sur- 
face will  transmit  308,700  B.  t.  u.  per  hour.  The  43  sq.  ft. 
of  flue-surface  will  transmit  26,875  B.  t.  u.  per  hour,  a 
total  of  335,575  B.  t.  u.  per  hour.  Fifteen  per  cent  of 
this  is  useless,  therefore  the  gross  transmission  that  is 
available  is  only  285,239  B.  t.  u.,  or  enough  to  carry  1,188 
sq.  ft.  It  will  be  seen  that  the  boiler  A  under  a  less 
powerful  fire  loses  in  a  larger  proportion  than  does 
boiler  B. 

It  should  be  understood,  however,  that  in  the  cases 
where  the  stack-temperature  falls  below  that  of  the 
water  as  it  circulates  in  the  boiler,  it  is  not  usual  to 
find  the  transmission  from  the  flue-surface  to  be  in  equal 
proportion  with  the  cases  where  the  stack-temperature 
is  above  the  temperature  of  the  circulating  water.  The 
friction  in  the  flue-surface  and  the  cooling  of  the  water 
at  the  stack-end  of  the  flue  often  create  conditions  that 
reduce  the  value  of  the  flue-surface  greatly  out  of  pro- 
portion to  the  figured  transmission,  and  never,  so  far 
as  I  have  observed,  to  the  advantage  of  the  boiler. 

There  is  a  tendency  on  the  part  of  some  manufactur- 
ers to  rather  overdo  the  matter  of  putting  in  a  large 
quantity  of  direct  heating  surface  and  cutting  down  the 
flue-surface.  The  steam-fitter  will  find  himself  about  as 
badly  off  in  one  case  as  in  the  other.  The  proportion  of 

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A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

flue-surface  to  direct  surface  is  one  for  experiment,  to 
quite  an  extent,  in  all  cast-iron  boilers.  It  is  reasonably 
certain,  however,  that  any  combination  of  surfaces,  which 
results  in  having  a  direct  surface  more  than  double  the 
flue-surface  in  square  feet,  will  be  difficult  to  control. 
While,  on  the  other  hand,  a  cast-iron  boiler  with  a  flue- 
surface  more  than  double  the  direct  surface  will  require 
a  powerful  draft  to  secure  the  required  results. 

This  side  of  the  question  can  be  well  illustrated  by 
testing  two  boilers.  Suppose  one  boiler  to  have  60  sq.  ft. 
of  direct  surface  and  30  sq.  ft.  of  flue-surface.  The 
other  boiler  to  have  30  sq.  ft.  direct  surface  and  60  sq.  ft. 
of  flue-surface.  Both  boilers  have  90  sq.  ft.  of  heating 
surface,  but  the  heating  value  of  the  two  boilers,  when 
tested  with  the  gases  in  the  fire-pot  at  1,200  deg.  F.  and 
stack-temperature  the  same  for  each,  say  400  deg.,  will 
be  greatly  different.  The  total  transmission  from  the 
first  one  will  be  648,000  B.  t.  u.  per  hour.  From  the  sec- 
ond one  396,000  B.  t.  u.  per  hour.  Deducting  the  15  per 
cent  loss,  not  accounted  for  from  the  piping  and  radia- 
tion, and  the  gross  capacity  of  the  first  boiler  for  steam- 
rating  is  2,295  sq.  ft.,  and  the  gross  capacity  of  the 
second  boiler  will  be  1,402  sq.  ft.,  a  difference  of  over 
61  per  cent  in  the  working  out  of  two  boilers,  each  hav- 
ing 90  sq.  ft.  of  heating  surface. 

In  the  light  of  the  facts  disclosed  in  the  discussions 
of  the  factor  of  combustion  as  shown  in  Tables  G  Z 
and  H  Z;  the  matter  of  fire-pot  size  as  shown  in  Table 
J  Z  and  its  bearing  on  the  time  factor;  the  necessity  of 
knowing  the  exact  amount  of  direct  heating  surface,  and 
the  total  amount  of  flue-surface  as  just  shown  by  illus- 
tration ;  of  what  material  value  to  the  steam-fitter,  to  the 
engineer,  to  the  house-owner,  or  to  the  student,  are  the 

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A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

various  data  in  the  ordinary  catalog  of  cast-iron  boilers 
for  house  heating?  If  the  manufacturers  have  seen  fit  to 
throw  the  burden  of  selection  and  garantee  upon  the 
steam-fitter  or  engineer,  why  should  not  the  steam-fitter 
and  engineer  demand  froni  the  producers  of  boilers,  the 
explicit  information  that  these  discussions  have  devel- 
oped it  is  necessary  for  them  to  have  in  order  that  they 
may  make  an  intelligent  choice  of  a  boiler  for  the  par- 
ticular heating  job  they  may  have  in  hand? 

The  question  of  heating  with  hot  water  as  the  medium 
for  distributing  the  heat  instead  of  steam  naturally  conies 
up  for  discussion  at  this  point. 


270 


SECTION  XXXVI. 


There  have  been  long  arguments  prepared  by  various 
authors  to  show  the  great  superiority  of  water  over  steam 
as  a  heating  medium.  It  is  not  my  purpose  to  present 
an  argument  in  terms  either  for  or  against  either  method. 

It  should  not  be  overlooked  by  the  trade,  however,  that 
when  the  manufacturers  changed  the  basis  of  rating 
steam-boilers,  and  thereby  changed  the  whole  problem 
of  steam-heating,  that  they  at  the  same  time  changed  the 
rating  basis  of  the  hot-water  heating  boiler  and  in  so 
doing  they  spoiled  many  of  the  arguments  as  to  the 
great  superiority  of  water  over  steam  as  a  heating  me- 
dium, when  each  system  is  planned  and  executed  by 
equally  competent  workmen. 

With  2-lb.  pressure  at  the  boiler,  we  have  seen  that  it  is 
not  to  be  expected  that  the  temperature  of  the  steam  in 
the  radiators  will  be  above  208  deg.  F.  (See  Tables  F 
and  F  F).  This  is  a  temperature  very  easily  produced 
in  any  open-tank  hot- water  job  where  the  tank  has  an 
elevation  of  15  ft.  or  more  above  the  boiler.  The  pro- 
duction of  the  vacuum-valve  and  a  regulator  that  will 
work  promptly  below  atmospheric  pressure  have  devel- 
oped an  entirely  new  condition  in  steam-heating  that 
advocates  of  hot-water  heating  must  very  carefully  con- 
template before  they  advance  the  old  stock  arguments  in 
regard  to  hot-water  heating. 

Under  these  changed  conditions  it  will  not  be  long  be- 
fore the  great  buying  public  will  demand  of  the  hot-water 
heating  fraternity  that  it  should  give  the  promptness  and 
certainty  of  action,  which  is  developed  by  steam  working 

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A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

tinder  less  than  atmospheric  pressure,  in  the  hot-water 
jobs  which  they  intend  to  install,  and  at  the  same  time 
maintain  a  fuel-account  not  in  excess  of  the  steam-job  as 
it  is  presented  in  a  first-class  steam-job  working  under 
pressure  at,  or  below,  that  of  the  atmosphere. 

This  may  sound  strangely  to  the  fitter  who  has  not 
taken  the  time  to  keep  himself  posted  on  the  new  de- 
velopments in  this  heating  problem.  If  any  one  of  my 
readers  has  an  abiding  faith  within  his  mind  cells  that 
the  possibilities  of  steam  entirely  supplanting  the  hot- 
water  heating  plant  for  household,  or  home-heating,  are 
great,  and  that  the  beginning  has  already  commenced, 
that  reader  is  probably  well  started  on  the  road  of  ulti- 
mate success  in  the  house-heating  business. 

It  is  reasonably  certain  that  during  the  ten  years  from 
1895  to  1905,  of  the  house-heating  in  this  country,  where 
either  steam  or  hot-water  heat  was  used,  fully  80  per 
cent  was  water. 

This  must  not  be  construed  to  mean  that  80  per  cent 
of  all  the  heating  in  this  country  during  those  years  was 
by  hot-water,  for  that  would  be  far  from  the  fact.  But 
of  the  homes,  the  houses  of  from  5  to  12,  or  15  rooms, 
the  proportion  of  hot-water  heating  to  steam  was  fully 
80  per  cent.  Of  the  steam  jobs,  only  a  very  small  per- 
centage, during  those  years,  were  constructed  on  the  vac- 
uum or  even  on  the  vapor-system. 

So  little  did  the  plumbing  and  heating  fraternity  know 
in  1894  in  regard  to  these  systems  as  applied  to  the  small 
house-heating  jobs  that  one  of  the  trade  journals  printed 
a  series  of  articles  on  the  vapor  and  vacuum-systems 
as  applied  to  house-heating.  Even  these  articles  did  not 
seem  to  rise  to  a  full  comprehension  of  the  magnitude 
of  the  question  they  were  presenting.  Some  time  later 

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A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

a  writer  in  the  same  journal  ventured  the  prediction  that 
"it  would  not  be  long  before  practically  every  heating 
job  would  be  a  vacuum,  a  vapor  or  an  accelerated  hot- 
water  system."  In  the  six  years  that  have  passed  since 
this  writer  made  his  prediction  there  has  been  a  greater 
gain  in  the  installation  of  vapor,  and  so-called  vacuum- 
steam  systems  for  house-heating,  than  was  made  in  the 
entire  heating  industry  so  far  as  it  relates  to  steam  and 
hot-water  heating  in  the  30  years  following  the  intro- 
duction of  steam-heating  by  Walworth  and  Nason. 

The  tremendous  strides  made  by  the  hot-water  men  in 
the  past  15  years  in  this  country  has,  perhaps,  been  only 
exceeded  in  the  mechanical  professions  by  the  electric- 
lighting  men,  in  so  far  as  household  development  is  con- 
cerned. 

It  is  comparatively  easy  to  determine  the  age,  or  be- 
ginning, of  steam-heating.  There  was  a  patent  issued 
June  1.3,  1835,  in  this  country  for  a  device  for  "warming 
buildings  by  radiated  and  steam-heat"  to  Robert  Rogers, 
of  South  Berwick,  Maine.  The  patent  office  building  was 
burned  in  183G  and  all  the  drawings  and  papers  connected 
with  the  Rogers  patent  for  steam-heating  were  destroyed. 
It  is  thought  that  Rogers  died  in  1836.  This  patent  was 
issued  at  least  seven  years  before  Walworth  and  Nason 
did  their  first  job.  In  fact,  this  patent  was  granted  be- 
fore Mr.  Nason  went  to  England  to  study  under  the  other 
great  American,  Angier  Perkins,  who  invented  a  steam- 
cannon  which  this  country  refused  to  buy,  but  which* 
Perkins  sold  to  the  English  government,  but  upon  such 
terms  that  he  was  practically  obliged  to  remain  forever 
in  England.  He  soon  turned  his  attention  to  heating  and, 
strangely  enough,  to  hot-water  heating  instead  of  steam. 
The  Perkins  sealed-pipe  system  was  the  outcome  of  his 

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A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

invention,  which  he  patented  in  this  country  as  well  as  in 
England. 

There  was  no  great  amount  of  steam-heating  at  that 
time  in  England,  but  hot  water  was  in  quite  general  use. 
That  he  should  have  turned  his  attention  to  hot  water 
as  his  medium  for  heat  is  even  more  unexplainable  when 
we  consider  the  fact  that  some  steam-heating  had  been 
practiced  in  England  before  1800,  and  the  process  pat- 
ented. Thomas  Tredgold,  in  his  book  on  "Principles  of 
Warming  and  Ventilating,"  published  in  1836,  states  that 
"Col.  William  Cook  first  suggested  the  idea  of  employ- 
ing steam  as  a  means  of  distributing  heat  in  1745."  An 
English  patent  was  issued  to  John  Hoyle,  of  Halifax, 
in  1791j  for  a  process  of  heating  by  steam.  This  is  un- 
doubtedly the  first  recognition  of  the  use  of  steam  as  a 
heating  medium  in  modern  times. 

The  beginning  of  hot-water  heating  is  lost  in  the  mists 
of  ages.  The  first  official  record,  which  I  have  been  able 
to  locate,  as  to  the  earliest  use  of  hot  water  as  a  heating 
medium,  is  in  one  of  the  Special  Reports  to  the  United 
States  Secretary  of  the  Treasury,  from  China,  in  1851. 
This  particular  report  was  made  at  the  request  of  the 
U.  S.  Government,  by  Dr.  D.  J.  McGowan,  who  was  sent 
to  China  to  make  an  investigation  and  report  to  the 
United  States  Government  in  regard  to  early  Chinese  in- 
ventions of  record.  Among  others  he  reported  the  in- 
vention of  a  water-clock  by  the  Duke  Chau,  who  was  a 
philosopher  and  inventor,  who  lived  before  Confucius. 
The  Chinese  records  describe  the  clock  as  being  attached 
to  a  furnace  which  heated  water  which  surrounded  the 
water-clock  and  kept  it  at  even  temperature  during  the 
winter  months.  This  same  inventor  is  claimed  to  have 
invented  a  compass  which  was  in  use  as  early  as  2,634 

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A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

years  before  the  Christian  era,  or  some  4,500  years  ago. 
Therefore  the  first  official  record  tor  hot-water  heating 
by  the  aid  of  a  furnace  refers  to  a  time  which  must  be 
fixed  as  corresponding  with  the  Chinese  claim  for  the 
compass.  Dr.  McGowan  in  his  report  does  not  fix  the 
time  directly,  but  he  states  that  the  same  man  who  in- 
vented the  furnace  and  connected  it  with  the  water-clock 
to  keep  it  from  freezing,  is  also  given  official  credit  for 
inventing  the  compass.  The  Encyclopedia  Britannica, 
Vol.  6,  page  226,  states  that  "the  earliest  references  to 
the  use  of  the  compass  are  to  be  found  in  Chinese  his- 
tory, from  which  we  learn  how,  in  the  64th  year  of  his 
"eign,  Emperor  Ho-ang-ti  (2634  B.  C.)  used  a  chariot 
equipped  with  a  compass." 

For  the  benefit  of  those  who  have  scruples  about  ac- 
cepting this  date  because  it  refers  to  a  time  previous  to 
rhe  date  of  the  Biblical  flood,  suppose  we  take  the  state- 
ment as  Dr.  McGowan  put  it,  "that  Duke  Chau  was  a 
philosopher  and  inventor  who  lived  before  Confucius." 
Well,  Confucius  was  born  550  years  before  Christ,  so  in 
any  way  one  looks  at  the  matter  the  first  official  report 
of  hot-water  heating  carries  with  it  evidences  of  a  very 
respectable  age.  So  old,  in  fact,  that  when  some  en- 
thusiastic old  fitter  tells  you  confidentially  that  he  helped 
install  the  first  hot-water  job  ever  constructed,  you  are 
entitled  to  the  belief  that  he  is  mistaken.  Other  refer- 
ences to  the  use  of  hot  water  as  a  heating  medium  can 
be  found  in  the  writings  of  numerous  early  authors. 
Perhaps  the  most  complete  descriptions  are  to  be  found 
in  the  works  of  the  elder  Pliny,  Publius  Papinius  Statius, 
and  Lucius  Anneus  Seneca ;  each  of  these  three  describes 
with  considerable  detail  the  method  of  heating  water 
contained  in  pipes,  one  end  of  which  was  passed  through 

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A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

a  fire,  and  show  that  this  method  was  practiced  long  be- 
fore the  Christian  era  commenced. 

The  descriptions  are  s-;  clear  that  there  have  been  made 
drawings  of  the  methods  used.  With  hardly  an  excep- 
tion the  plan  follows  the  lines  of  many  constructions  in 
use  today  in  this  country.  The  piping  used  in  those  old 
days  was  made  of  brass  instead  of  iron.  In  fact,  it  ap- 
pears that  in  a  period  of  over  2,000  years,  we  have  prac- 
tically added  nothing  to  the  knowledge  of  heating  bathing 
pools  by  hot-water  circulation.  And  judging  from  the 
description  of  the  heating  arrangements  in  a  private 
house  owned  by  a  Roman  aristocrat,  as  given  by  Auson- 
ius  about  the  year  350  A.  D.,  the  average  hot-water  job 
of  today  has  but  little  improvement  to  show  for  the 
nearly  1,600  years  that  have  elapsed  between  that  day 
and  this.  The  use  of  hot  water  circulated  through  pipes 
for  heating  appears  to  have  been  discovered,  used, 
dropped  from  use  only  to  be  rediscovered,  several  times 
since  its  first  expression  some  thousands  of  years  ago. 
And  yet,  it  is  only  within  a  period  covered  by  the  last 
half-century  that  anything  approaching  scientific  inves- 
tigation and  application  of  what  we,  today,  term  scien- 
tific methods,  has  been  attempted. 

To  a  very  great  extent  investigation  has  been  directed 
to  problems  in  steam-heating.  And  to  a  very  great  ex- 
tent to  the  problems  that  apply  to  big  installations,  oper- 
ated under  heavy  pressures. 

One  reason  that  the  scientific  investigation  of  hot- 
water  heating  has  not  been  more  fully  attempted  can 
probably  be  attributed  to  the  fact  that  hot-water  as  a 
heating  medium  rarely,  if  ever,  makes  any  noise  or  dis- 
turbance of  any  kind,  however  badly  treated.  It  does  its 
best,  however  poor  its  setting.  With  steam  it  is  differ- 

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A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

ent.  The  moment  the  steam  job  finds  itself  in  anything 
but  conditions  of  perfect  satisfaction  it  begins  to  "speak 
for  itself  in  no  uncertain  tones."  It  will  "squeal"  on 
the  incompetent  that  constructed  it.  It  will  hammer  and 
knock  in  a  most  exasperating  manner,  something  that  the 
quiet  hot-water  job  never  does,  and  yet  the  hot-water  as 
a  heating  medium  responds  even  more  emphatically  to 
proper  environment  in  the  cost  of  maintenance. 

The  present  demand  that  steam  boilers  shall  maintain 
the  heat  in  the  radiators  with  a  pressure  at  the  boiler  of 
not  to  exceed  2  Ib.  compels  the  fitter  to  produce  a  job 
for  steam  carrying  less  pressure  at  the  boiler  than  does 
any  open-tank  hot-water  job  where  the  expansion- tank 
is  10  ft.  above  the  boiler. 

A  head  of  water  of  1  ft.  is  equal  to  0.4331  Ib.  pressure 
per  sq.  in.  If  the  water  in  the  expansion  tank  is  5  ft.  above 
the  boiler  the  pressure  at  the  boiler  will  be  2.165  Ib.,  or 
nearly  1-6  of  a  pound  greater  pressure  than  the  steam- 
job  is  to  carry.  As  the  majority  of  residence-jobs  will 
average  to  have  the  expansion-tank  at  least  20  to  25  ft. 
above  the  boiler,  the  pressure  at  the  boiler  is  from  8.66 
to  10.83  Ib.,  or  from  4  to  5  times  that  of  the  steam-job. 
This  natural  pressure,  due  to  the  head  or  elevation  of  the 
expansion  tank,  is  frequently  increased  by  the  use  of  one 
or  another  of  the  patent  devices  for  sealing  the  job  for 
another  10-lb,  pressure,  thus  presenting  the  curious  con- 
dition of  having  an  alleged  hot-water  open-tank  system 
working  under  a  boiler-pressure  that  is  practically  pro- 
hibited in  modern  house-heating  with  steam.  These  are 
things  the  hot-water  contractor  must  seriously  consider. 
The  new  steam  practice  without  the  aid  of  appliances  for 
strictly  vapor-heating,  or  any  of  the  various  so-called 
vacuum-accessories,  produces  results  that  in  economy  of 

277 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

fuel,  or  ease  of  care  and  attention,  often  are  more  favor- 
able than  many  hot-water  jobs. 

If  it  is  needed  for  the  steam-fitter  to  remodel  his  ideas 
and  practice,  because  of  the  new  conditions  created  by  the 
change  in  the  rating  of  steam-boilers  (and  it  certainly 
is),  it  is  still  more  important  that  the  hot-water  fitter  and 
engineer  gets  busy  with  the  new  problems  which  the  new 
fashion  of  rating  water-boilers  has  forced  to  the  front. 
The  old  rules  are  as  much  out  of  place  in  the  practice 
of  hot-water  heating  as  they  are  for  steam  and  for  the 
same  reasons. 


278 


SECTION  XXXVII. 


With  the  advent  of  gages  and  regulators  and  graduated 
valves  that  will  work  with  absolute  accuracy  on  steam- 
jobs  which  are  producing  the  steam  below  the  atmospheric 
pressure,  the  supremacy  of  water-heat  over  steam  is  se- 
riously threatened  at  least,  and  if  the  hot-water  man 
expects  to  hold  his  place  in  the  race  he  will  need  to  stop 
just  guessing,  and  get  down  to  solid  knowing  the  hot- 
water  heating  business. 

To  be  a  first-class  hot-water  heating  man  today  requires 
a  better  and  more  complete  knowledge  of  the  science  of 
heating  than  is  required  for  steam-fitting.  That  this  is 
true  is  shown  by  the  almost  universal  failure  of  me- 
chanics who  do  steam-fitting  fairly  well,  to  do  equally 
good  hot-water  heating. 

In  those  sections  of  the  country  where  the  heating 
season  is  very  long,  some  artificial  heat  being  required  at 
times  during  7  or  8  months  of  the  year,  hot  water  will 
remain  somewhat  a  favorite  on  account  of  its  evenness  of 
heat.  But  even  there,  unless  the  hot-water  men  keep  pace 
with  the  advances  being  made  in  steam-heating  for  small 
residences,  they  will  certainly  find  themselves  distanced 
in  the  race  for  contracts. 

Twenty  years  ago  a  writer  on  heating  said :  "Heating 
apparatus  of  all  kinds — hot  water,  hot  steam,  or  hot  air — 
are  not  necessarily  a  success  or  a  failure  because  belong- 
ing to  either  system,  but  really  and  simply  because  they 
have  had  more  or  less  brains  engrafted  and  transferred 
into  them  by  the  designer  and  engineer.  Establish  any 

279 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

rational  standard  of  construction,  operation  and  result  for 
either  system,  and  then  compare  the  failures  of  each  to 
reach  such  a  standard,  and  I  do  not  know  on  whose 
shoulders — the  steam,  the  water,  or  the  hot-air  furnace 
men — the  sword  would  fall  with  the  greatest  force." 

This  rather  drastic  comment  is  even  more  applicable 
today  than  it  was  20  years  ago,  for  the  percentage  of 
men  who  try  to  do  each  kind  of  heating  is  larger  than 
then,  and  the  proportion  that  are  trying  to  fit  old-time 
rules  and  styles  to  the  new  ratings,  is  so  great  that  prob- 
ably never  in  the  history  of  the  steam  and  water-heating 
business  has  the  amount  of  unintelligent  work  been 
greater  than  during  the  past  few  years,  since  the  change 
of  ratings. 

The  many  failures  have  had  the  influence,  however,  of 
calling  the  attention  of  the  trade  to  the  fact  that  more 
care  must  be  given  to  the  little  things  now  than  in  the 
past. 

Strangely  enough,  the  greatest  factor  in  the  develop- 
ment of  the  desire  to  do  better  work  in  hot-water  heat- 
ing was  the  introduction  of  the  various  forms  of  the  so- 
called  heat  generators. 

The  trade  had  been  taught  that  in  hot-water  heating 
that  there  is  but  one  element  present  after  the  apparatus 
is  once  filled  with  water  and  put  to  work.  The  water  fills 
all  spaces,  and  closes  them  against  the  entrance  of  the 
air-element.  That  in  the  water- job  the  motive  power  is 
not  pressure  obtained  from  the  boiler  as  in  the  steam- 
job,  but  that  it  comes  from  the  difference  in  the  weight 
of  the  colder  and  the  hotter  water  in  the  pipes,  and  many 
of  the  smaller  fitters  really  professed  to  believe  that  a 
temperature  above  the  boiling-point  of  212  deg.  could  not 
be  attained  in  an  open-tank  system,  and  often  questioned 

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A     Practical    Manual    of    Steam    and    Hot-Water    Heating 

the  accuracy  of  the  thermometers  sent  for  use  at  trie 
boiler. 

Everything  that  we  have  discussed  in  relation  to  the 
figuring  for  heating  by  steam  is  applied  in  the  same  way 
for  hot-water  heating.  Even  more  care  should  be  exer- 
cised in  the  examination  of  the  chimney  conditions  than 
might  be  needed  for  a  steam- job.  The  area  in  square 
inches  of  the  proposed  chimney  for  a  hot-water  installa- 
tion is  of  the  utmost  importance.  Especial  care  should 
be  exercised  to  make  certain  that  the  area  of  the  smallest 
place  in  the  chimney  is  well  in  excess  of  the  area  of  the 
smoke-opening  called  for  by  the  manufacturer  of  the  pro- 
posed boiler.  There  should  be  a  more  careful  examina- 
tion of  this  chimney  proposition  when  a  hot-water  boiler 
is  to  be  used  than  for  a  steam-boiler,  and  the  area  must 
never  be  less  than  the  area  of  the  smoke-flue  provided 
for  the  hot-water  boiler  to  be  used. 

It  is  impossible  to  state  this  detail  of  the  installation 
of  a  hot-water  boiler  too  strongly.  A  careful  study  of 
tables  GZ,  HZ  and  KZ,  in  the  light  of  the  fact  that  all  hot- 
water  boilers  are  now  rated  on  the  basis  of  a  temperature 
at  the  boiler  of  only  180  deg.  F.,  will  disclose  abundant 
reason  for  the  emphatic  insistence,  on  the  part  of  the 
hot-water  fitter,  that  the  owner  shall  furnish  a  chimney 
of  ample  size  and  quality  of  draft. 

Water  being  the  greatest  absorber  of  heat  known,  and 
as  one  great  source  of  circulation  in  the  ordinary  house- 
heating  job  is  the  difference  in  the  weight  of  the  hot  and 
colder  water  in  the  circulating  pipes,  and  as  the  tem- 
perature fixed  by  the  new  ratings  is  so  low,  180  deg.,  it 
becomes  a  matter  of  the  utmost  concern  to  the  fitter,  who 
must  garantee  the  job,  that  the  draft  for  the  boiler  shall 
be  of  the  best,  and  that  the  volume  of  it  shall  be  ample, 

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A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

in  order  that  a  constant  combustion  at  this  very  low  tem- 
perature shall  be  secured. 

It  is  one  thing  to  have  just  draft  enough  to  produce 
the  disintegration  of  coal  at  a  low  temperature,  and  quite 
another  to  have  coal  burn  at  a  low  temperature,  although 
the  net  number  of  pounds  of  coal  passed  through  the 
furnace  may  be  practically  the  same  for  each  condition. 
In  order  to  produce  actual  combustion  of  the  coal  the 
chimney  must  not  only  have  a  strong  draft  per  square 
inch  of  its  area,  but  it  must  have  an  area,  free  and  clear, 
equal  or  in  excess  of  the  area  provided  by  the  manufac- 
turer of  the  boiler  for  the  passage  from  the  boiler  of  the 
smoke,  coal  gases  and  the  air  needed  for  good  combus- 
tion ®f  the  coal.  Every  word  said  in  the  opening  chap- 
ters of  this  series  in  regard  to  the  chimney  for  a  steam- 
boiler  applies  with  equal  force  to  the  hot-water  boiler. 

Unless  the  chimney-conditions  are  right  as  the  starting 
point  for  the  hot- water  job,  it  is  downright  foolishness  to 
attempt  to  produce  a  thoroughly  good  hot-water  job. 

The  hot-water  fitter  must  go  over  identically  the  same 
methods  for  securing  the  loss  of  heat  from  the  rooms 
that  the  steam-fitter  is  obliged  to  use.  Until  the  ques- 
tions of  selecting  the  boiler  and  sizing  the  pipes  present 
themselves  for  decision,  the  various  steps  of  the  steam- 
heating  men  and  of  the  hot-water  heating  men  are,  or 
should  be,  identically  the  same. 

But  with  the  method  of  selecting  the  boiler  certain  dif- 
ferences in  the  manner  of  deciding  what  is  best  for  the 
individual  job  begins  to  show. 

It  may  be  well  to  state  them  side  by  side  so  that  they 
can  be  seen  at  a  glance. 


282 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 


Steam  System. 

To  select  a  steam-boiler 
the  fitter  must  consider 
the  following: 

1.  The    height    of    water 

line. 

2.  The    pressure    he    can 

carry  at  boiler. 

3.  The  pressure   required 

at  the  end  of  the 
supply-line  where 
the  drop  is  made 
below  the  water- 
line. 

4.  The  grade  of  the  pip- 

ing. 


5.  The  kind  of  coal  to  be 

used. 

6.  The  number  of    hours 

heat  is  to  be  fur- 
nished with  one 
firing. 


7.  The  size  of  fire-pot 
required  to  meet 
the  required  condi- 
tions. 


Hot-water  System. 

.  To  select  a  hot-water 
boiler  the  fitter  must  con- 
sider the  following: 

(1)  The     height     of     the 

boiler. 

(2)  The  grade  of  the  pip- 

ing. 

(3)  The   kind   of   coal   to 

be  used. 


(4)  The  number  of  hours 

heat  is  to  be  fur- 
nished with  one  fir- 
ing. 

(5)  The    size    of    fire-pot 

required  to  meet 
the  conditions. 

(6)  The  proportions  of  di- 

rect and  indirect- 
heating  surface  in 
boiler  best  adapted 
to  the  chimney- 
draft. 

(7)  The  stack-temperature 

required  to  produce 
manufacturers'  rat- 
ing. 


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A    Practical    Manual    of    Steam    and    Hot-Water    Heating 


8.  The  proportion  of  di-       (8)   The      area      of      the 


rect-heating  surface 
to  indirect  in  the 
boiler  best  adapted 
to  the  chimney- 
draft. 

9.  The  stack-temperature 
required  to  produce 
the  manufacturers' 
rating. 

10.  The  area  of  the  smoke, 
gases  and  air-open- 
ing at  boiler. 


smoke,     gases     and 
air-opening  at  boiler. 


SECTION  XXXVIII. 


The  two  things  that  the  steam-fitter  must  consider  with 
care  when  he  is  to  select  a  boiler,  that  the  hot-water  fitter 
is  not  required  to  consider  particularly,  are,  pressure  at 
the  boiler  and  pressure  at  the  point  where  the  point  of 
equalization  occurs  in  the  piping.  The  new  ratings  hav- 
ing brought  the  maximum  temperatures  of  the  two  heat- 
ing mediums  within  40  deg.  Fahr.  of  each  other,  the  hot- 
water  man  who  is  required  to  show  a  saving  in  fuel  as 
compared  with  the  steam  job  of  same  size,  needs  to  know 
the  positive  value  of  each  and  every  step  in  the  construc- 
tion of  a  hot-water  apparatus. 

The  first  thing  he  must  consider,  with  even  more  care 
than  the  steam  job  requires,  will  be  the  boiler.  While 
he  does  not  have  to  figure  primarily  on  boiler  pressure, 
as  shown  on  a  gage  affixed  to  the  boiler,  we  shall  find 
that  height  of  the  water  in  the  boiler,  as  well  as  the 
quantity  of  water  that  the  boiler  contains,  may  be  of 
commanding  importance  for  an  individual  installation. 

In  order  to  make  this  clear  it  will  be  necessary  to 
study  the  principles  involved  in  the  circulation  of  hot- 
water  which  is  heated  at  one  point  and  then  circulated 
through  pipes  back  to  the  point  of  heating,  to  be  heated 
again  to  the  higher  temperature,  that  the  circulation  may 
continue. 

In  a  general  way,  almost  every  one  has  an  idea,  which 
is  more  or  less  correct,  in  regard  to  what  produces  the 
circulation  in  a  hot-water  job.  But  it  is  important  that 
the  exact  view  of  the  question,  upon  which  the  state- 

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A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

ments  that  will  follow  in  regard  to  hot-water  heating 
are  based,  shall  ^  be  fully  set  forth  at  this  time  in  order 
that  no  confusion  of  ideas  shall  occur.  The  necessity  of 
this  will  be  all  the  more  apparent  when  the  fitter  comes 
to  consider  the  question  as  to  whether  or  not  he  will  add 
to  his  piping  any  one  of  the  so-called  "heat-generators," 
"heat-retainers,"  "circulation-accelerators,"  and  other  de- 
scriptively-named patented  articles,  which  from  time  to 
time  appear  on  the  market.  The  first  thing,  then,  is  to 
get  a  clear  idea  of  what  produces  the  circulation  of  the 
water  in  an  ordinary  heating  job,  and  then  to  examine 
into  the  things  that  either  retard  or  improve  the  circula- 
tion of  the  water  as  a  heating  medium. 

The  foundation  of  the  theory  of  hot-water  circulation 
in  pipes  is  based  upon  three  facts :  First,  the  fact  that 
one  cubic  foot  of  water  at  the  temperature,  or  point  of 
its  greatest  density,  or  at  39.2  deg.  Fahr.,  weighs  at  the 
sea-level  nearly  62^  Ib.  (62.425),  while  a  cubic  foot  of 
water  at  212  deg.  weighs  not  quite  60  Ib.  (59.844  Ib.) 
(Encyclopedia  Britannica,  Vol.  12,  page  480;  Subject, 
Hydromechanics).  There  will  be  found  slight  variations 
in  tables  presented  by  different  authors  as  to  the  weight 
of  one  cubic  foot  of  water  at  different  degrees  of  tem- 
perature, but  the  change  from  the  table  KZ  is  so  slight 
that  it  does  not  affect  the  results  of  the  needed  calcula- 
tions for  a  small  heating  apparatus  and  need  not  be  con- 
sidered as  of  moment  in  the  present  discussion. 

The  second  fact  is  that  if  heat  is  applied  when  water  is 
at  its  point  of  greatest  density  at  the  sea-level,  the  water 
soon  begins  to  expand,  to  occupy  more  space  than  it  did 
at  39.2  deg.  temperature.  In  other  words,  the  mass  of 
water  is  actually  bigger  than  it  was  before  the  heat  was 
applied  and  it  keeps  on  growing  larger  in  its  mass,  or 

Continued  on  page  288 
286 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 


TABLE  KZ. 

Weight  of  1  cubic 

foot  of  water  at  the  various 

temper- 

atures   usually   found 

within   the   range   of  house 

heating 

by  hot  water. 

Temp,  of  Water, 

Wt.  in  Lb.  of  1  Cu.  Ft. 

Relative 

Deg.  Fahr. 

Water  at  this  Temp. 

Volume. 

40 

62.42 

1.00001 

50 

62.41 

1.00025 

60 

62.37 

1.00083 

70 

62.31 

1.00196 

80 

62.23 

1.00334 

90 

62.13 

1.00497 

100 

62.02 

1.01491 

110 

61.89 

1.00901 

120 

61.74 

1.00748 

130 

61.56 

1.01409 

140 

61.37 

1.01678 

145 

61.28 

1.01828 

150 

61.18 

1.01983 

155 

61.08 

1.02145 

160 

60.98 

1.02309 

165 

60.87 

1.02480 

170 

60.77 

1.02656 

175 

60.66 

1.02836 

180 

60.55 

1.03024 

185 

60.44 

1.03213 

190 

60.32 

1.03414 

200 

60.07 

1.03820 

212 

59.76 

1.04332 

220 

59.64 

230 

59.38 

250 

58.81 

270 

58.21 

300 

57.25 

The  above  table  has  been  prepared  by  taking  items 
from  a  number  of  different  authorities  who  gave  the 
formula  used  in  preparing  their  tables,  and  is  believed 
to  be  sufficiently  accurate  for  the  work  to  which  it  should 

287 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

be  applied.  No  one  should  attempt  to  seal  a  job  to  a 
pressure  of  65  Ib.  actual  or  50  Ib.  gage  pressure,  which 
is  about  what  300  degrees  temp,  would  mean.  The  table 
has  been  carried  to  that  point  because  among  some  of 
the  cut-throat-sell-them-cheaper  concerns  the  size  of  pip- 
ing sent  out  with  the  material,  as  well  as  the  size  of  the 
radiators  used,  indicate  that  that  pressure  is  intended. 

expanding,  until  it  reaches  its  limit  of  expansion  at  212 
deg.  if  it  is  not  confined  in  a  closed  apparatus.  When  the 
water  is  confined  in  a  closed  apparatus  in  such  a  manner 
that  the  water  at  no  point  is  in  contact  with  the  atmos- 
phere, the  pressure  that  can  be  exerted  by  the  continued 
application  of  heat  is  bounded  only  by  the  strength  of 
the  material  that  composes  the  envelope. 

The  third  fact  is  that  when  water  is  at  its  point  of 
greatest  density  at  the  sea-level,  or  at  about  40  deg. 
Fahr.,  it  is  also  at  its  point  of  greatest  compressibility. 
This  fact  is  of  the  utmost  importance  to  the  heating  pro- 
fession. This  last  fact  is  at  the  very  bottom  of  the  whole 
hot-water  heating  problem.  No  man  who  intends  to  do 
hot-water  heating  has  any  right  to  overlook  this  tre- 
mendous fact  in  nature  for  one  single  moment  when  he 
is  considering  the  question  of  the  piping  outfit  for  a 
given  job. 

One  cubic  foot  of  water  at  the  sea-level  at  its  point  of 
greatest  density  has  been  compressed  by  the  strength  of 
Nature  into  the  smallest  compass  that  it  can  occupy.  If 
the  pressure  of  a  column  of  water  a  mile  in  height  should 
be  applied  to  it  the  amount  that  it  could  be  compressed 
would  not  be  enough  to  permit  the  addition  of  another 
half-pint  of  liquid  into  the  cubic  foot  that  was  under 
pressure.  It  was  compressed  to  the  limit  when  it  just 

288 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

filled  the  cubic  foot  of  space  at  the  sea-level  at  39.2  deg. 
Fahr.  and  atmospheric  pressure  only  applied.  So  little, 
in  fact,  has  this  matter  of  the  utter  impossibility  of  com- 
pressing water  into  a  smaller  compass  by  pressure,  and 
the  constant  expansion  in  bulk,  or  mass,  under  the  appli- 
cation of  heat  been  understood  among  the  trade  that  it 
is  a  very  common  thing  for  the  fitter  engaged  in  the 
hot-water  heating  business  to  tell  the  prospective  cus- 
tomer that  the  difference  in  weight  between  the  hot  and 
cold  water  produces  the  circulation.  While  this  differ- 
ence in  weight  is  one  of  the  things  that  tends  to  produce 
the  circulation  it  is  far  from  the  only  thing  or  the  most 
important  thing  in  the  phenomenon  of  circulating  water 
through  pipes  for  heating  purposes. 


289 


SECTION  XXXIX. 


I  will  try  to  make  this  clear  with  the  aid  of  Fig.  24  and 
Table  KZ.  We  will  assume  that  Fig.  24  represents  a 
receptacle  B  which  may  be  called  a  boiler,  and  tubes  or 
pipes  P  connected  to  the  top  and  bottom  of  the  recep- 
tacle B,  and  also  open  to  the  air  at  point  T.  The  lower 
portion  of  the  receptacle  B  does  not  contain  water  but  is 
arranged  to  maintain  fire.  We  will  assume  that  the  dis- 
tance from  E1  to  E2  is  34  ft.  and  from  the  point  at  G  at 
the  bottom  of  receptacle  B  to  the  T  on  the  tube  P  is  also 
34  ft.  The  tube  or  pipe  may  be  of  any  size,  but  for  our 
illustration  we  will  call  it  a  3-in.  pipe.  From  Table  LZ 
we  learn  that  one  foot  in  length  of  3-in.  pipe  will  con- 
tain .38  of  a  gal.  of  water  and  that  19.5  ft.  in  length  will 
contain  one  cubic  foot  of  water  which  will  weigh  when  at 
its  point  of  greatest  density  62.425  Ib. 

The  importance  to  the  hot-water  heating  man  of  this 
statement  as  to  the  weight  of  a  cubic  foot  of  water  at  its 
point  of  greatest  density  has  not  usually  been  brought 
forward  by  the  writers  on  hot-water  heating.  Why  it  has 
been  so  slightly  mentioned  is  another  of  the  many  strange 
things  to  be  encountered  when  looking  up  this  heating 
problem  in  so  far  as  it  is  related  to  hot-water  heating. 
When  a  receptacle  contains  one  cubic  foot  of  water  at 
the  sea-level,  of  the  temperature  39.2  deg.  Fahr.,  practi- 
cally the  most  water  that  can  be  pressed  into  one  cubic 
foot  of  space  is  in  that  receptacle.  If  a  pressure  equal 
to  that  of  a  column  of  water  5,000  feet  high  should  be 
placed  on  it,  the  water  could  not  be  compressed  enough 
to  increase  the  weight  to  63  Ib.  or  enough  to  add  one 

290 


A    Practical    Manual    of    Steam    and    Hot-Water   .Heating 

gill  more  water.  It  is  because  of  this  fact,  the  impos- 
sibility of  compressing  water  more  than  it  is  compressed 
by  Nature  at  atmospheric  pressure,  that  one  pound  of 
distilled  water  at  the  sea-level  and  at  its  point  of  great- 
est density  is  used  for  obtaining  the  British  thermal  units 
that  we  talk  about  so  frequently. 

For  the  same  reason  the  specific  gravity  of  anything  is 
determined  by  comparison  with  water  at  the  sea-level 
when  at  a  given  temperature. 

It  is  probable  that  this  attribute  of  water  is  also  the 
cause  of  its  being  the  greatest  absorber  of  heat  known. 
At  simply  atmospheric  pressure  of  14.7  Ib.  at  the  sea- 
level,  water  will  always  absorb  exactly  the  same  quantity 
of  heat  in  producing  the  same  condition.  If  open  to  the 
air  it  will  burst  the  bond  of  atmospheric  pressure  at  a 
temperature  of  212  deg.  Fahr.  Confine  the  water  in  a 
closed  receptacle  and  continue  to  apply  heat  and  the 
water  will  continue  to  absorb  it  until  the  pressure  of  the 
expanding  of  the  incompressible  water  will  burst  the 
bond  that  holds  it.  In  this,  water  is  in  no  way  different 
from  what  we  call  steam  in  its  action  under  similar  con- 
ditions, except  that  its  weight  and  density  per  cubic  foot 
of  space  is  much  greater  than  steam. 

One  feature  of  the  process  of  heating  water  in  a  boiler 
or  heating  system  that  is  of  the  greatest  moment  to  the 
hot-water  fitter  is  that  each  additional  foot  in  height  that 
a  body  of  water  contains  between  the  bottom  and  the 
top  of  the  column  that  is  exposed  to  the  air  at  the  top, 
increases  the  pressure  at  the  bottom  of  the  column,  and 
the  temperature  of  the  water  at  the  bottom  will  always 
be  higher  when  heat  is  applied  to  the  bottom  than  it  can 
possibly  be  at  the  top  where  it  comes  into  contact  with 
the  air. 

291 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

It  is  probable  that  the  circulation  in  an  open-tank  sys- 
tem of  water-heating  is  due  more  to  this  cause  than  to 
the  difference  in  the  weight  of  the  ascending  and  descend- 
ing columns  of  water,  and  that  the  difference  in  weight  is 
of  much  less  consequence  than  the  difference  in  power 
needed  to  expand  one  cubic  inch  of  water  at  the  top  of 


u 


TV. 


2  5 


4.77 


6  8-b 


9  / 


U5L8 


AT  BOTTOM  OF  Bot££P 
?50° 


173° 


/7/' 


TEMP.  174-  HT  Ci'BiC  FT.  60. 68 1-&. 

PRESS VKE   ?  16 


/75 


4.  '33 


177* 


6.5 


/?£ 


£,66 


/C.S4- 


179'  wr  cvrr  6C  S7ie 


13.  0 


wr  ci/e/c  Fr. 

60.77  LO. 


TEMP  /69 


168 


167" 


166 


'•  165  WT.CUB^ 
FT.  60.871&. 


-164-  WT.CU6. 
FT.  60  9  LB 


Fig.  24. 

the  column,  where  it  is  in  contact  with  no  pressure 
greater  than  the  atmosphere,  and  the  power  needed  to  ex- 
pand one  cubic  inch  of  the  water  at  the  bottom  of  the 
column,  where  the  pressure  in  an  average  house  job  may 
easily  be  produced  from  30  to  40  Ib.  per  sq.  in.  greater 
than  at  the  top. 

292 


A    Practical    Manual    of    Steam    and    Hot- Water    Heating 

In  Fig.  24:  the  tube  P  is  to  be  considered  as  being  31  ft. 
from  the  bottom  of  elbow  E2  to  the  bottom  of  elbow  El. 
At  the  top  of  the  pipe  PI  a  tee  permits  the  water  in  the 
pipe  to  come  into  contact  with  the  atmosphere  by  means 
of  the  extension  of  the  pipe  1  to  the  expansion  tank. 

As  a  column  of  water  one  foot  high  exerts  a  pressure 
of  .4335  Ib.  per  sq.  in.  at  its  base  when  at  the  tempera- 
ture of  40  deg.  at  the  sea-level,  it  follows  that  the  pres- 
sure at  the  bottom  of  a  column  34  ft.  high  will  be  14.7  Ib. 
above  that  exercised  by  the  atmosphere  on  the  top  of  the 
column. 

When  heat  is  applied  to  the  receptacle  B  circulation 
does  not  start  instantly,  as  is  sometimes  stated,  any  more 
than  circulation  starts  instantly  in  a  pan  of  water  set 
over  a  fire  on  a  stove.  The  depth  of  the  water  in  the 
pan  creates  a  certain  pressure  at  the  bottom  of  the  pan 
on  the  particles  which  constitute  the  element  we  call 
water,  and  the  more  depth  the  greater  pressure.  This 
pressure  determines  the  length  of  time  which,  under  a 
specified  temperature  of  heat,  will  be  required  before  cir- 
culation of  the  particles  will  actually  begin. 

In  a  hot-water  heating  apparatus  the  water  will  not 
begin  to  circulate  until  some  particle  of  the  water  has 
absorbed  heat  enough  to  overcome  whatever  pressure 
rests  upon  it.  As  cold  water  cannot  be  further  com- 
pressed it  follows  that  no  particle  of  water  can  rise  until 
it  overcomes  whatever  pressure  rest^  on  it. 


293 


SECTION  XL, 


In  Fig.  24  the  pressure  on  the  bottom  of  the  system 
is  that  due  to  a  column  of  water  34  ft.  high  or  14.7  Ib. 
above -atmosphere,  to  which  must  be  added  the  pressure 
of  the  atmosphere,  or  14.7  Ib.  more,  therefore,  each  par- 
ticle of  wrater  at  the  bottom  before  it  can  start  up  from 
the  bottom  must  reach  a  temperature  of  at  least  250  deg. 
Fahr.,  as  it  is  only  at  that  temperature  that  a  pressure 
of  that  amount  is  equalized.  When  one  particle  has  ab- 
sorbed that  much  heat  it  will  have  the  power  to  overcome 
the  pressure  on  it  and  to  rise  up  in  the  receptacle  be- 
cause it  has  increased  in  strength,  and  although  it  now 
possesses  the  power  to  shoot  straight  to  the  top  of  the 
column  if  unobstructed,  it  does  not  do  so.  The  first  ob- 
struction to  its  progress  up  is  the  fact  that  as  soon  as  it 
finds  itself  under  a  less  pressure  it  immediately  expands 
itself  in  size,  and  in  doing  this  parts  with  some  of  its  ac- 
quired heat  to  the  particles  with  which  it  comes  into  con- 
tact. As  soon  as  it  has  parted  with  so  much  power  that 
it  is  equal  in  size  and  strength  to  the  particles  with  which 
it  is  in  contact,  and  can  no  longer  overcome  the  pressure 
put  on  it  by  the  height  of  water  above  it,  it  will  either  re- 
main in  a  nearly  stationary  position  until  it  receives  more 
heat  by  contact  with  other  rising  particles,  or  it  will  drop 
towards  the  bottom  again  and  remain  there  until  it  re- 
ceives the  necessary  heat  to  give  it  the  power  to  over- 
come the  pressure  on  it  and  to  rise  toward  the  top  again. 
It  is  this  action  that  keeps  the  water  circulating.  The 
difference  in  the  weight  between  the  warmer  and  cooler 

294 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

water  in  the  flow  pipes  is  a  secondary  movement  which 
is  produced  by,  and  from,  the  first  cause  just  explained. 

Let  us  investigate  this  matter  a  bit  with  the  aid  of 
Fig.  24.  We  will  suppose  that  the  system  is  filled  with 
water  when  it  has  a  temperature  of  62  deg.  Fahr.,  when 
each  cubic  foot  will  weigh  62.355  Ib.  From  Table  LZ  it 
is  seen  that  each  lineal  foot  of  3-in.  pipe  will  hold  0.051 
of  a  cubic  foot  of  water.  The  34-ft.  pipe  will  hold  1.73 
cubic  feet.  One  cubic  foot  of  water  measures  or  con- 
tains 7.4805  gals.  One  gallon  of  water  weighs  8.3356  Ib. 
The  total  weight  of  the  water  in  the  upright  34-ft.  col- 
umns El— E2,  will  be  107  1-3  (7.4805X8.3356X1-73  = 
107  1-3.) 

Assuming  the  total  length  of  the  horizontal  pipes  to 
be  36  ft.  the  total  length  of  all  the  3-in.  pipe  suggested 
by  Fig.  24  will  be  102  ft.  (32+36+34),  and  the  pipe 
alone  will  hold  over  5  cubic  feet  of  water,  weighing  324 
Ib.,  all  of  which  must  be  put  into  motion  to  produce  cir- 
culation,, and  in  addition  to  the  water  which  the  pipe  will 
hold  there  is  an  additional  quantity  in  the  receptacle  or 
boiler  itself  that  must  be  made  to  move. 

If  we  apply  heat  to  the  receptacle  B  for  a  sufficient 
length  of  time  and  in  sufficient  amount  the"  temperature 
of  all  the  water  in  the  system  will  become  raised  to  any 
desired  temperature  below  212  deg.  at  any  point  in  the 
system,  if  applied  under  conditions  usually  found  in  the 
average  house-heating  job.  To  accomplish  this,  however, 
all  that  weight  of  water  must  be  moved  up  and  down 
and  over  a  great  many  times,  and  something  more  than 
the  difference  in  the  weight  of  the  rising  and  falling 
columns  of  water  in  pipes  PI  and  P3  will  enter  into  the 
process. 

As  boilers  for  hot-water  heating  are  now  rated  as  be- 

295 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

ing  capable  of  heating  to  180  deg.  the  usual  amount  of 
water  held  in  a  heating  system  with  the  amount  of  radi- 
ating surface  each  boiler  is  rated  to  carry,  commencing 
at  the  point  where  the  pipe  is  attached  to  the  boiler  (a,  on 
Fig.  2-t),  and  to  return  to  the  boiler  at  160  deg.,  perhaps 

TABLE  LZ. 

Showing  the  quantity  of  water  held  in  one  lineal  foot  of 
pounds  and  ounces.  The  length  in  feet  of  each  size  of  pipe 
the  cubic  feet  held  in  one  lineal  foot  of  each  size  of  pipe  at 

Weight  in 


Size  of  Pipe, 

Gallons  in 

1-Ft. 

Length 

Diameter   in    In. 

1-Ft.    Length. 

Lb. 

Oz. 

1 

0.045 

0 

6 

154 

0.077 

0 

10 

iK> 

0.105 

0 

14 

2 

0.174 

1 

7 

2/2 

0.249 

2 

1 

3 

0.384 

3 

3 

3^ 

0.514 

4 

5 

4 

0.661 

5 

8 

4^ 

0.829 

6 

15 

5 

1.062 

8 

10 

6 

1.489 

12 

8 

7 

1.998 

16 

12 

8 

2.596 

21 

11 

9 

3.259 

27 

3 

10 

4.095 

34 

2 

11 

4.937 

41 

2 

32 

5.875 

49 

0 

it  will  be  well  to  examine  into  this  difference  of  weight 
proposition  from  those  temperatures.  Especially  so,  as 
we  have  already  seen  that  the  actual  pressure  on  the 
crown-sheet  of  a  hot-water  boiler  before  there  is  any  heat 
applied  is  several  times  greater  than  the  new  ratings  for 
steam  boilers  permit  for  a  steam  job. 

296 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 


With  the  simple  lines  of  Fig.  24  to  aid  us  we  arrive  at 
the  following  fact:  That  the  water  contained  in  first 
foot  of  pipe  attached  to  the  top  of  the  boiler  weighs  .02 
Ib.  less  than  the  water  in  the  last  foot  of  pipe  which  is 
connected  to  the  boiler  as  the  return. 

TABLE  L,  Z. 

pipe  in  gallons,   quarts,  pints  and  gills.     Also  the  weight  in 
that   will   be   required   to   hold   1   cubic  foot   of  water.     Also 
40  degrees  Fahr.  and  at  sea  level. 
Length  in  Lin.  Ft. 


Required  to  Hold 

Quantity  Held, 

Cu.  Ft.  in  1 

1  Cu.  Ft.  of  Water. 

Gal. 

Qt. 

Pt. 

Gill. 

Lin.  Ft.  Length. 

167 

0 

0 

0 

I/ 

0.006 

96^ 

0 

0 

0 

2/2 

0.011 

70% 

0 

0 

0 

3/ 

0.014 

43 

0 

0 

1 

1/2 

0.023 

30 

0 

1 

0 

0 

0.034 

19.5 

0 

1 

1 

o/ 

0.051 

14.5 

0 

o 

0 

o/ 

0.068 

11.33 

0 

2 

1 

1/8 

0.088 

9 

0 

3 

0 

2/ 

0.111 

7 

1 

0 

0 

2 

0.136 

5 

1 

1 

1 

3  5/7 

0.199 

3.75 

2 

0 

0 

0 

0.267 

2.88 

2 

2 

0 

1   5/7 

0.347 

2.29 

3 

1 

0 

0   5/7 

0.436 

1.83 

4 

0 

0 

3 

0.547 

1.52 

4 

3 

1 

2 

0.659 

1.27 

5 

3 

1 

0 

0.785 

One  foot  in  length  of  a  3-in.  pipe  holds  2.97  Ib.  water 
of  180  deg.  temperature.  The  same  length  and  size  of 
pipe  holds  2.99  Ib.  of  water  of  160  deg.  temperature,  a 
difference  of  .02  Ib.  The  equivalent  of  .01  Ib.  is  70 
grains.  The  total  difference,  then,  in  practically  3  Ib.  of 
water  at  180  deg.  and  1GO  deg.  is  140  grains.  As 

297 


A     Practical    Manual    of     Steam    and    Hot-Water    Heating 

grains  equal  one  ounce,  the  difference  in  the  weight  of 
these  three  first  and  last  pounds  is  less  than  one-third  of 
an  ounce.  If  we  are  to  take  the  statement  usually  handed 
out  by  the  hot-water  fitters  in  regard  to  what  causes  the 
water  to  circulate,  we  must  conclude  that  .01  Ib.  weight 
in  a  hot-water  apparatus  is  many  hundred  times  more 
effective  than  anywhere  else  on  earth.  Four  inches  of 
the  3-in.  pipe  will  hold  1  Ib.  of  water,  and  the  last  pound 
is  the  heaviest  and  has  the  greatest  velocity  of  any  pound 
of  water  in  the  system  and,  therefore,  is  the  propelling 
power  that  moves  the  whole  mass  according  to  the  propo- 
sition that  is  usually  advanced  by  fitters  as  -  being  the 
cause  or  power  which  circulates  the  water  in  the  heat- 
ing pipes. 

The  absurdity  of  the  proposition  is  evident  the  mo- 
ment that  any  person  takes  the  time  to  examine  it  as  we 
have  in  this  case.  That  over  300  Ib.  of  water  will,  or 
can,  be  elevated  over  30  ft.  and  forced  through  more  than 
100  ft.  in  length  of  3-in.  pipe  with  elbows  to  turn  in  the 
distance  by  a  pressure  of  less  than  50  grains  to  the  pound, 
is  hardly  probable. 

It  is  time  that  the  advocate^  of  hot-water  heating  get 
down  to  practical  facts  in  regard  to  the  circulation  of 
water  in  this  very  excellent  method  of  heating,  and  they 
will  certainly  have  to  do  so  if  they  expect  to  hold  their 
own  in  the  competition  which  is  arising  from  the  vapor- 
steam,  vacuum,  non-pressure  steam  and  other  similar 
projects  of  the  steam  men  who  are  giving  thought  to  the 
development  of  their  business. 


298 


SECTION  XLI. 


The  plain  fact  of  the  matter  of  the  circulation  of  hot- 
water  through  the  pipes  in  an  open-tank  system  can  be 
fairly  stated  by  saying  that  the  same  heat  that  ex- 
pands water  until  it  breaks  into  the  steam  which  is 
driven  by  the  pressure  generated  in  the  process 
through  the  pipes,  when  applied  to  pipes  that  are  first 
filled  with  cold  water  which  at  some  high  point  in  the 
system  is  permitted  to  come  into  contact  with  the  at- 
mosphere pressure,  expands  the  water  nearly  one- 
quarter  of  its  bulk  between  the  temperature  points  of 
40  and  212  deg.  And  as  water  is  not  compressible  to 
any  extent,  this  expansion  presents  a  moving  force  to 
the  particles  of  water  which  eventually  lifts  them  to 
the  point  of  highest  elevation,  at  which  point  each  par- 
ticle finds  itself  against  the  slight  pressure  created  by 
the  height  of  the  column  of  expanded  water  in  the 
pipe  to  the  open  air,  which  may  be  connected  with 
the  main  pipe  at  that  point.  The  particles  of  water 
in  the  main  pipe  itself  have  less  power  of  resistance 
against  the  now  slightly  expanded  water  than  is  of- 
fered by  the  weight  of  water  in  the  so-called  expan- 
sion-tank, and  the  warm  water  follows  the  path  of 
least  resistance  to  the  pipes  that  drop  to  the  boiler; 
and  here  the  careful  observer  finds  that  in  the  ordi- 
nary hot-water  job  when  running  at  its  rated  capacity 
of  180  deg.,  at  the  boiler,  160  deg.,  at  the  return,  if  he 
is  to  have  proper  circulation  he  must  have  a  static 
or  head-pressure  greater  at  the  foot  of  his  return  pipe 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

than  he  has  in  the  top  of  the  boiler.  In  this  there  is 
no  difference  between  steam  and  water  jobs.  It  is  at 
this  point,  and  at  this  point  only,  that  the  difference 
in  the  weight  of  the  ascending  and  descending  col- 
umns of  water  cuts  the  greatest  figure  in  the  general 
vjuestion  of  hot-water  circulation. 

In  a  gravity  steam  job  the  only  way  that  the  water 
is  returned  to  the  boiler  is  by  having  the  pressure 
of  the  return  water  at  the  point  where  it  enters  the 
boiler  greater  than  the  pressure  of  the  steam  on  the 
water  in  the  boiler.  The  difference  in  the  average 
steam  job  of  house-heating  is  2  ounces  per  sq.  in. 
greater  at  the  bottom  of  the  return  pipe  than  the  pres- 
sure on  the  bottom  of  the  crown-sheet  of  the  boiler. 

In  a  well-proportioned  hot-water  job  the  difference 
in  the  pressure  between  the  water  on  the  crown-sheet 
of  the  boiler  and  on  the  bottom  of  the  drop-pipe  at 
the  point  where  the  pipe  for  the  return  enters  the 
boiler,  when  the  apparatus  is  wrorking  at  the  rated  tem- 
perature of  180  deg.  at  the  boiler,  varies  in  accord- 
ance with  the  height  of  the  ascending  column  of  wat- 
er and  the  length  of  the  descending  column  coupled 
with  the  average  temperature  difference  of  the  de- 
scending and  ascending  columns  of  water. 

When  the  water  contained  in  the  system  indicated 
by  Fig.  24  is  all  of  the  same  temperature  there  will 
be  no  circulation.  It  would  make  no  difference 
whether  the  temperature  of  all  the  water  was  40  deg. 
or  180  deg.,  the  result  would  be  the  same,  because  so 
long  as  the  temperature  of  the  entire  mass  remains 
the  same,  the  pressure  at  every  point  of  the  system 

300 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

bears  the  same  proportionate  relation  to  every  other  point. 
As  soon  as  additional  heat  is  applied  to  the  bottom 
of  receptacle  B  (which  will  represent  the  crown-sheet 
of  a  boiler  the  lowest  part  of  the  water  in  which  is 
under  the  same  head-pressure  as  the  water  in  the  bot- 
tom of  the  pipe  P-4  when  all  the  water  is  of  the  same 
temperature),  the  water  immediately  over  the  fire 
begins  to  absorb  the  increased  heat  and  continues  to 
absorb  it  until  the  expanding  particles  of  water  have 
received  power  enough  to  overcome  the  head-pres- 
sure on  that  bottom  layer,  if  I  can  use  such  an  ex- 
pression in  regard  to  water.  These  particles  will  in 
every  case  reach  a  temperature  equal  to  the  tempera- 
ture of  steam  at  the  same  pressure.  In  the  case  of 
Fig.  24  we  have  taken  the  height  to  be  34  ft.  from 
crown-sheet  to  the  top  of  pipe  P-2.  This  height  rep- 
resents a  pressure  of  14.7  Ib.  due  to  the  static  head, 
or  height  of  the  column  of  water. 

From  table  M-2,  or  any  table  of  the  properties  of 
steam,  one  will  find  that  this  represents  a  pressure 
equal  to  that  of  the  same  amount  as  the  atmosphere. 
In  other  words,  of  the  atmosphere  itself  and  another, 
or  gage  pressure,  two  atmospheres  or  an  absolute 
pressure  of  29.3  Ib.  The  temperature  of  these  parti- 
cles at  the  moment  of  their  overcoming  the  total  pres- 
sure upon  them  will  be,  therefore,  the  same  as  that 
of  steam  at  the  same  pressure,  or  250  deg. 

The  weight  of  one  cubic  inch  of  these  expanded  par- 
ticles would  be  236  grains,  while  the  weight  of  one 
cubic  inch  of  the  water  in  the  return  pipe  at  the  point 
of  its  connecting  with  the  boiler  would  be  in  accord- 
ance with  the  temperature  of  the  whole  body  of  wat- 

301 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

er  at  the  time  the  heat  is  applied,  provided  that  there 
is  no  circulation  yet  in  actual  progress. 

If  that  temperature  be  62  deg.,  then  the  weight  of 
one  cubic  inch  will  be  259  grains  and  the  difference 
in  the  weight  of  one  cubic  inch  is  23  grains,  or  about 
one-nineteenth  of  one  ounce.  This  difference  con- 
stantly diminishes  as  the  contents  of  the  two  pipes 
approach  each  other  in  temperature.  With  the  water 
in  the  supply  pipe  at  180  deg.  at  the  boiler  and  160 
deg.  at  the  return,  the  difference  in  the  weight  of  one 
cubic  inch  will  be  about  one-fortieth  of  an  ounce  as 
compared  with  the  very  bottom  of  the  boiler,  and 
about  one-two-hundred-and-eighteenths  of  an  ounce 
if  compared  with  the  weight  of  a  cubic  inch  of  water 
as  it  enters  the  supply  pipe  at  180  deg.  If  we  com- 
pare the  weight  of  one  cubic  foot  of  water  at  180  deg. 
with  the  weight  of  a  cubic  foot  at  160  deg.  we  find  the 
difference  to  be  .43  Ib.  or  a  trifle  less  than  7  ounces.  .01 
of  a  Ib.  equals  70  grains.  437.5  grains  in  one  ounce.  We 
find  that  the  weight  of  the  water  in  1  ft.  of  3-in.  pipe  at 
180  deg.  will  be  2.97  Ib.  and  at  160  deg.  will  be  2.99  Ib.,  a 
difference  of  .02  of  a  Ib.,  or  less  than  one-third  of  an 
ounce. 

From  the  foregoing  it  is  evident  that  there  must  be 
something  besides  the  difference  in  the  weight  of  the 
two  columns  of  water  that  produces  the  circulation  in  a 
hot-water  job.  It  will  hardly  be  a  competent  reply  to  say 
that  the  height  of  the  fall  of  the  return  water  furnishes 
the  motive  power,  it  seems  to  me,  although  that  is  usually 
the  offhand  statement.  If  the  pipe  containing  the  water 
is  tightly  sealed,  and  heat  is  applied  to  the  pipe  at  its 
lowest  point,  the  pressure  which  would  be  created  would 
be  equal  at  every  part,  but  the  expansion  of  the  particles 

302 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

of  water  would  constantly  grow  less  as  they  receded  from 
the  point  where  the  heat  was  applied.  To  a  great  extent, 
it  is  this  expanding  and  contracting  of  the  particles  of  the 
water  that  gives  action  or  circulation  to  the  water  in  the 
heating  system,  whether  the  system  be  an  open-tank  or 
a  sealed  system.  The  terrific  force  that  can  be  developed 
by  the  constant  application  of  heat  to  water  in  a  sealed 
pipe  is  well  known.  At  this  point  please  bear  in  mind 
that  water  at  about  40  deg.  is  compressed  to  a  point 
almost  beyond  the  power  of  man  to  compress  farther  its 
particles.  Apply  heat  in  sufficient  quantity  and  the  par- 
ticles increase  in  bulk,  and  of  necessity  crowd  or  press 
those  that  have  not  increased  in  bulk  the  same  degree. 
The  greater  the  pressure  on  the  particles  to  which  the 
heat  is  applied,  the  greater  the  quantity  of  heat  that  must 
be  applied  to  cause  expansion  and  circulation. 

The  amount  of  heat  that  will  raise  the  temperature  of 
a  cubic  foot  of  water  from  40  deg.  to  212  deg.  will  ex- 
pand it  to  nearly  1.25  cu.  ft.  in  size  if  exposed  to  the  air. 
In  gallons  this  means  that  approximately  8  gal.  of  water 
will  swell  to  about  10  gal.  The  enormous  power  that  is 
generated  in  this  process  and  which  is  the  prime  cause  of 
the  circulation  will  be  understood  better,  perhaps,  if  we 
notice  what  happens  to  100  ft.  in  length  of  the  iron-pipe 
that  contains  the  water.  Starting  the  heat  when  the 
water  is  at  40  deg.  and  continuing  it  until  the  whole  body 
of  water  is  at  212  deg.,  we  find  that  the  100  ft.  of  iron 
pipe  has  been  stretched  in  length  about  one  and  one-quar- 
ter inch.  That  is  the  power  that  produces  the  circulation, 
aided  by  the  difference  in  weight. 


303 


A    Practical    Manual    erf    Steam    and    Hot-Water    Heating 


TABLE    MZ. 

Velocity  of  water  in  pipes  in  feet  per  hour  when  the 
radiator  at  various  temperatures,  from  161  degrees  to  180 

dicated,  no  allowance 


Water  enters 

161 

165 

Water  leaves 

160 

160 

Difference. 

1 

5 

i 

Drop  of  Return 

Feet  Flow 

Feet  Flow 

in  Feet. 

per  Hour. 

per  Hour. 

1 

370 

868 

5 

824 

1,936 

10 

1,166 

2,740 

15 

1,429 

3,358 

20 

1,653 

3,744 

25 

1,843 

4,334 

30 

2,003 

4,752 

35 

2,192 

5,112 

40 

2,336 

5,472 

45 

2,477 

5,796 

50 

2,610 

6,120 

While  this  table  is  made  with  the  return  water  as  of 
160  degrees  there  will  be  but  a  very  slight  difference  at 
other  temperatures  usually  required  in  hot  water  heat- 
ing. For  instance,  if  the  entering  water  is  at  220  degs. 
and  the  water  as  it  leaves  the  radiator  is  at  210  degs. 
the  difference  in  feet  of  flow  per  hour  is  only  about  200 
feet  with  no  allowance  for  friction.  To  illustrate  this 
and  at  the  same  time  explain  the  method  of  producing 
the  Table  M  Z :  The  weight  of  one  cubic  foot  of  water 
at  220  deg.  is  59.64  Ib.  and  a  cubic  foot  at  210  weighs 
59.82  Ib.  A  difference  of  18/100  of  one  pound. 

Without  an  allowance  for  friction  the  velocity  of  drop 
per  foot  as  produced  by  gravity  is  32.16  feet,  but  it  has 

304 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 


TABLE    MZ. 

water  leaves  the  radiator  at  160  degrees  and  enters  the 
degrees,  when  the  return  drop  is  from  1  to  50  feet  as  in- 
being  made  for  friction. 


170 
160 

10 


175 
160 

15 


180 
160 

20 


Feet  Flow 

Feet  Flow 

Feet  Flow 

per  Hour. 

per  Hour. 

per  Hour. 

1,199 

1,444 

1,714 

2,678 

3,308 

3,816 

3,744 

4,536 

5,436 

4,644 

5,724 

6,624 

5,364 

6,588 

7,668 

5,976 

7,416 

8,568 

6,552 

8,100 

9,396 

6,804 

8,748 

10,152 

7,488 

9,324 

10,836 

8,028 

9,900 

11,520 

8,460 

10,440 

12,132 

the  same  to  overcome  in  the  rising  column,  therefore 
the  two  columns  equal  32.16X2=64.32.  The  distance 
dropped  is  to  be  10  feet;  then  64.32X10=643.20.  The 
difference  in  weight  is  .18  Ib.  more  643.20X.18=115.7760. 
This  must  be  divided  by  the  total  weight  of  one  cubic  foot 
of  each  column  for  both  move  at  the  same  time.  59.82+ 
59.64=119.46  and  the  square  root  of  the  quotient  from 
this  division  will  be  the  velocity  per  second  without  any 
allowance  for  friction.  (115.7760-^119.46=0.969,  the 
square  root  of  which  is  0.984 — ft.  per  second ;  3600  sec- 
onds to  the  hour.  .984X3600=3542.  feet  per  hour  with- 
out allowance  for  friction.  Table  N  Z  under  the  difference 
of  10  deg.  with  the  return  water  at  160  deg.  gives  the 

305 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

flow  as  3744,  a  difference  of  202  ft.  in  an  hour,  so  small 
that  it  would  not  be  of  consequence. 

Having  found  the  velocity  in  feet  that  the  water  will 
move,  the  next  thing  is  to  find  the  cubic  feet  of  water 
that  will  be  required  to  supply  various  conditions  that 
may  arise.  The  manner  of  finding  this  out  is  clearly 
shown  in  Table  N  Z. 


TABLE    N    2. 

Showing  the  cubic  feet  of  water  required  per  hour  per  square  foot  of  radiating 
surface  at  different  temperatures  and  at  different  rates  of  loss  as  the  water  passes 
through  the  radiating  surface. 


Item 
1 

9 


Temperature  of 

water.  140  150  160 

Weight  per  cu. 

ft.  at  above 

temperature.  61.37         61.18         60.90 

3  Temperature  of 

room.  70  70  70 

4  Dif.  bet.  temp, 
water  and  air  in 

room.  70  80  90 

5  B.t.u.  emitted  per 
hour  per  sq.   ft. 
of  radiator  per 

deg.    diff.  -    1.4  1.45  1.45 

6  Total  B.t.u.  per 
sq.  ft.  per  hour. 

(Item  4xltem  5.)     98  116  130 

7  Lb.  water  cooled 

1  deg.  Fahr.  in  pro- 
ducing   1    B.t.u.       1  1 

8  Lb.  water  required 
to  be  supplied  to 
each  sq.  ft.  per 
hour  if  cooled 

5  degs.   passing 
through  radiator. 
(Item  6 -f- Item  8.) 

thus 
(98-^-5  =  19.6.)        19.6  23.2  26. 

9  Lb.  when  cooled 
10  deg.  in  passing. 

(Item  6^- Item  9.)    9.8  11.6  13. 

10  Lb.  when  cooled 

15  deg.  in  passing.    6.5  7.7 

11  Lb.  when  cooled 

20  deg.  in  passing.    4.9  5.8  6.5 

12  Cu.   ft.   required 
per  sq.  ft.  per 
hour  if  cooled  5 
deg.   in  circuit. 
(Item  9-^Item  2) 

thus, 

(19.6  -=-  61.37  = 
0.319.)  0.319         0.379         0.426 

13  Cu.  ft.  required 
if  cooled  10  deg. 
in  circuit. 
(Item  9-f-  Item  2) 

thus, 

(9.8  -^  61.37  = 
0.159)  0.159         0.189         0.213 

14  Cu.  ft.  required 
if  cooled  15  deg. 
in  circuit. 

(Item  10^-Item  2.)     0.106         0.126         0.142 

15  Cu.  ft.  required 
if  cooled  20  deg. 
in  circuit. 

(Item  H-=-Item  2.)    0.079         0.096         0.107 


170 

60.77 
70 

100 


150 


15. 
10. 


0.493 


0.246 


180 

60.55 

70 

110 

1.5 
165 

1 


33. 

16.5 
11. 

8.25 


0.545 


0.273 


0.164         0.182 


190 

60.32 

70 

120 

1.5 
180 

1 


36. 

18. 

12. 

9. 


0.597 


200 

60.07 

70 

130 


41.6 

20.8 
13.8 
10.4 


0.298         0.343 


210 

59.82 
70 

140 


44. 

22. 

14.9 

11.2 


0.692         0.749 


0.374 


0.199         0.230         0.249 


0.123         0.137         0.150         0.173         0.187 


SECTION  XLII. 


But  what  gets  the  water  into  the  boiler  against  the 
combined  head-pressure  and  heat-pressure  at  the  crown- 
sheet  ? 

As  previously  stated,  the  process  is  exactly  the  same  as 
with  the  steam  boiler.  In  the  hot-water  boiler  there  is  an 
area  of  surface  exposed  to  the  action  of  the  heat  very 
much  greater  than  the  area  of  the  connecting  pipes  that 
circulate  the  water  after  it  is  heated.  Because  of  this  the 
total  quantity  of  water  that  is  actually  expanded  enough 
to  rise  to  some  considerable  distance  higher  than  the  high- 
est point  in  the  boiler  cannot  all  get  through  the  pipe 
opening,  with  the  result  that  a  forced  circulation  is  set 
up  in  the  boiler  which  sends  the  water  into  the  pipe  as 
it  starts  on  the  circuit  in  much  the  same  manner  that 
water  is  sent  out  of  a  hose  nozzle.  As  soon  as  a  com- 
plete circulation  is  established  the  weight  of  all  the  water 
in  the  boiler  itself  is  lighter  per  cubic  foot  than  the  pres- 
sure due  to  head  at  the  top  of  the  boiler  where  the  cir- 
culating pipe  commences,  and  as  it  cannot  get  out  of  the 
boiler  a  pressure  is  created  artificially  that  at  least  equal- 
izes the  static  head  at  that  point,  and  as  the  heat  in  the 
water  increases,  this  expansion,  or  pressure,  extends 
higher  in  the  pipe  of  an  overhead  system,  or  farther  in 
the  main  of  a  circuit  system,  very  much  as  happens  with 
a  steam  job.  This  crowding  of  particles  and  loss  of 
strength  as  they  get  away  from  the  boiler  is  in  every 
way  similar  to  the  action  of  steam. 

The  net  result  of  this  is  that,  while  the  total  depth  of 

307 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 


a=o 


SYSTEM 

HOTTEST 


LIN£  OF 

IN      <* 
THE     WftTER  ftT* 
SELECT5P  PRESSVfc 


TANK  PIPE 
COHHECTfP 


f?£TVf?N  P/PE 


Fig.   25. 


water  is  the  same  in  the  supply  and  return  as  indicated  in 
Fig.  24,  the  pressure  equalizes  at  some  point  higher  than 
the  top  of  the  boiler,  thus  making  the  unequalized  por- 

308 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

tion  of  the  return  pipe  longer  than  the   supply,  some- 
times by  several  feet. 

Assuming  that  the  loss  of  20  deg.,  from  180  to  160,  is 
absolutely  uniform  per  lineal  foot  for  an  apparatus  as 


Fig.   27. 


indicated  in  Fig.  24,  the  point  of  average  temperature 
would  be  at  E-2.  At  170  deg.  the  water  has  an  expansion 
or  pressure  force  to  exert  against  the  down  column  of 
about  .25  lb.  per  sq.  in.,  which  added  to  the  longer  fall 


309 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

in  the  return  pipe  produces  the  extra  pressure  needed 
to  keep  the  water  continually  flowing  into  the  boiler 
through  the  return  until  such  time  as  the  heat  in  the 
boiler  growing  less  fails  to  expand  the  water  sufficiently 
to  overcome  the  static  head.  When  that  time  arrives 
there  will  still  be  some  particles  of  water  receiving  suf- 
ficient heat  to  expand  slightly  for  a  time  but  they  will 
be  robbed  of  their  heat  by  the  other  particles  in  the 
boiler  before  they  force  themselves  out  of  the  boiler  and 
soon  the  active  movement  of  the  particles  ceases. 

Here  is  where  the  hot-water  system  gets  its  greatest 
gain  over  gravity  steam  jobs.  The  gravity  steam  job 
having  but  a  comparatively  small  quantity  of  water  to 
raise  to  212  deg.,  gets  heat  to  the  radiators  in  an  effective 
quantity  sooner  than  can  usually  be  secured  from  hot- 
water,  but  the  steam  has  nothing  but  the  latent  heat  of 
the  steam  to  give  out,  966  B.  t.  u.  per  Ib.  of  steam. 
When  the  heat  in  the  boiler  of  the  steam- job  falls  below 
the  point  where  the  water  in  the  boiler  can  be  maintained 
at  212  deg.,  the  heat  from  the  radiators  ceases  as  quickly 
as  it  started. 

With  the  water  job  it  is  different.  The  water  not  only 
has  a  large  bulk  from  which  to  deliver  heat,  but  it  con- 
tinues to  receive  the  heat  from  the  fire  and  deliver  it  to 
the  radiators  to  the  extent  of  at  least  100  deg.  of  tem- 
perature after  the  steam-point  ceases.  This  refers  of 
course  to  the  open-tank  systems  for  water,  and  gravity 
systems  for  steam. 

With  any  sort  of  a  sealed-tank  system  of  hot-water 
the  case  is  somewhat  different.  Given  an  overhead,  or 
attic-circuit  water-system  sealed  to  25  Ib.  pressure  at  its 
highest  point,  and  pipes,  smaller  than  would  be  used  for 
a  gravity  steam  job  limited  to  2  Ib.  at  boiler,  can  be  used. 

310 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

The  radiators  would  be  smaller  than  would  be  required 
for  the  steam  job.     Reserving  20  per  cent  of  the  usable 


Fig.  26. 

pressure  for  emergencies,  the  radiation  can  be  figured  on 
the  basis  of  20  Ib.  pressure  or  at  a  temperature  difference 

311 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

of  190  deg.,  but  all  the  heat  of  the  fire  above  about  100 
cleg,  will  be  delivered  from  the  radiators  to  the  room. 

All  the  patent  heat-generators,  so-called  intensifiers, 
and  the  like  that  have  come  on  the  market  within  the  past 
few  years  are  nothing  but  carefully  prepared  seals  op- 
erating  at  anywhere  from  10  Ib.  to  30  Ib.  pressure.  A 
well-adjusted  weight  safety  valve  set  as  per  Fig.  25  is  a 
safer  and  more  sensible  attachment  than  some  of  these 
patent  seals  now  on  the  market.  The  weighted  safety 
valve  has  also  the  compensating  feature  that  you  can 
Know  exactly  what  pressure  you  are  sealing  in  the  boiler. 

If  you  are  going  into  the  sealed  hot-water  business, 
and  within  reasonable  limits,  there  should  be  no  great 
objection  to  it,  keep  the  regulation  of  the  pressure  within 
your  own  control. 

The  overhead  hot-water  system  as  indicated  in  Fig.  26 
is  undoubtedly  the  best  theoretically  for  either  open-tank 
or  sealed  jobs.  Next  to  that  I  would  say  turn  the  over- 
head system  into  the  cellar.  You  will  then  have  a  single- 
main  pipe-system,  on  the  whole  the  most  practical  for 
either  steam  or  water  heating  for  ordinary  house-work. 
This  is  shown  in  Fig.  27.  The  old-fashioned  manifold 
system,  where  each  riser  was  connected  with  the  boiler,  * 
is  not  used  to  any  great  extent  at  this  time,  but  there 
often  arise  conditions  where  its  use  is  a  matter  of  good 
practice.  This  is  quite  often  the  case  where  indirect 
radiators  for  a  hot-water  job  are  required.  In  most  in- 
stances it  will  be  better  to  feed  the  indirect  stack  from  a 
simple  circuit  directly  from  and  to  the  boiler  rather  than 
to  attempt  to  take  it  from  the  main  circuit  that  is  to 
supply  the  direct  radiators  on  the  floors  above. 

Piping  for  hot-water  heating,  and  piping  properly,  is  a 
careful  and  should  be  a  painstaking  piece  of  work. 

312 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

Water  cannot  be  compressed  as  steam  or  air  may  be  at 
:>ne  place  and  allowed  to  expand  in  another  through  the 
vagaries  of  piping  and  secure  for  the  fitter  the  best  re- 
mits. 


313 


SECTION  XLIII. 


In  hot-water  heating,  because  of  the  non-compressi- 
bility of  the  water,  and  in  the  open-tank  systems  of  the 
very  slow  velocity  of  the  water  through  the  pipes,  the 
fitter  who  cares  for  his  reputation  as  an  engineer,  or 
who  has  a  pride  in  giving  to  his  clients  the  best  possible 
equipment  for  his  heating-plant,  will  be  exceedingly  care- 
ful in  the  selection  of  the  pipe-sizes. 

The  craze  for  small  pipe  that  has  swept  over  the  coun- 
try in  regard  to  steam-work  seems  to  have  been  grow- 
ing in  favor  with  the  cut-price-get-a-job-at-low-price 
men  in  the  hot-water  heating-business.  Hundreds  of 
water-heating  men  have  badly  crippled  the  effectiveness 
of  their  work  from  a  senseless  selection  'of  pipe-sizes. 

Consider  what  the  heat  which  emanates  from  a  hot- 
water  radiator  is  derived  from.  We  have  seen  that  water 
is  a  fluid  which  is  practically  compressed  to  the  limit 
when  we  start  with  it.  We  also  know  that  in  order  to 
have  the  radiator  deliver  one  heat-unit,  1  Ib.  of  water 
must  be  cooled  1  deg.  Fahr.  It  follows,  then,  as  the 
simplest  sort  of  reasoning,  that  if  the  fitter  desires  to 
have  one  square  foot  of  hot-water  radiator  surface  yield 
any  given  number  of  heat-units  per  hour,  it  will  be  nec- 
essary to  supply  that  square  foot  of  surface  with  a  cer- 
tain number  of  pounds  of  water  per  hour  at  the  tempera- 
ture required. 

For  instance,  with  water  at  180  deg.  at  the  boiler  and 
160  deg.  at  the  return,  the  average  temperature  is  170 
deg.  If  the  room  is  at  70  deg.  the  difference  is  100  deg. 

314 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

Given  a  three-column  radiator  delivering  to  the  room  1.5 
B.  t.  u.  per  degree  of  difference  per  square  foot  per 
hour,  or  150  B.  t.  u.  or  1  deg.  from  150  Ib.  of  water. 
Assuming  that  the  water  enters  the  radiator  at  170  deg. 
and  leaves  it  at  160  deg.,  the  radiator  surface  has  taken 
as  an  average  1/15  of  the  heat  that  it  is  designed  that  it 
shall  take  from  the  water  in  one  hour;  and  to  complete 
the  requirements,  the  same  amount  of  water  at  the  same 
temperature  must  flow  through  that  same  radiator  15 
times  in  one  hour.  And  in  order  to  accomplish  that,  it 
is  certain  that  a  definite  pressure  and  a  definite  quantity 
of  water-flow  must  be  maintained.  To  obtain  this  there 
must  be  a  definite  relation  between  the  size  of  the  pipe, 
the  friction  incurred,  the  velocity  attained,  the  quantity 
of  water  delivered,  and  the  loss  that  is  to  occur  in  the 
passage  through  the  system.  In  an  open-tank  system  the 
velocity  under  the  most  favorable  conditions  must  be 
low,  but  there  will  be'  a  variety  of  velocities  in  the  or- 
dinary house- job. 

The  height  that  a  radiator  sets  above  the  boiler  has  a 
very  great  bearing  on  the  velocity  of  the  water  through 
it  and,  of  course,  this  in  turn  has  a  bearing  on  the  size 
of  pipe  that  will  be  required  to  deliver  the  needed  pounds 
of  water  to  furnish  the  150  B.  t.  u.  per  hour.  Table  MZ 
gives  the  number  of  feet  per  minute  which  the  water  will 
move  in  a  properly  piped  hot-water  open-tank  system. 

Table  N  Z  makes  no  provision  for  friction  in  the  pipes. 
Having  found  the  cubic  feet  of  water  to  be  moved  per 
hour  at  an  accepted  loss  of  temperature  as  shown  in 
Table  N  Z  Items  12  to  15,  inclusive,  and  the  velocity  that 
the  water  must  assume  to  produce  that  loss  (Table  M 
Z),  it  is  evident  that  if  the  total  number  of  feet  of  radi- 
ating surface  on  a  job  is  multiplied  by  the  loss  from  one 

315 


A    Practical    Manual    of    Steam    and    Hot- Water    Heating 

square  foot  and  the  sum  thus  found  is  divided  by  the 
hourly  velocity,  the  area  that  will  be  required  in  the  pipe 
will  be  disclosed.  But  this  will  not  provide  for  the  fric- 
tion, as  these  tables  only  show  the  theoretical  movement 
of  the  water  in  the  pipes. 

The  fitter  for  hot-water  who  is  to  give  his  client  the 
best  results  possible  will  give  this  matter  of  friction  the 
most  careful  attention.  In  laying  out  the  job  the  fitter 
will  use  the  least  possible  number  of  elbows  and  other 
friction-producing  fittings.  In  the  long  run  it  will  be 
found  that  the  use  of  the  patent  fittings,  like  the  O.  S. 
fittings,  on  risers  and  other  suitable  places,  the  Eureka 
fittings  for  the  main  supply  pipe,  or  the  Phelps  combi- 
nation fitting,  are  decidedly  better  than  the  regular  fit- 
tings, and  will  tend  to  produce  better  results  in  the  circu- 
lation and  also  reduce  the  net  cost  of  the  work. 

Labor,  at  present  prices,  is  decidedly  more  expensive 
than  the  difference  in  the  price  of  these  patent  fittings 
and  the  price  of  the  common  ones.  In  addition  the  fit- 
tings mentioned,  and  others  that  may  be  not  so  well 
known,  present  a  smoother  surface  to  the  water  and  also 
to  the  eye. 

In  most  cases  where  the  piping,  including  the  addition 
to  be  made  because  of  fittings  (see  Section  XVIII)  does 
not  exceed  in  measured  length  100  feet,  the  pipe-sizes 
found  by  the  use  of  the  tables  will  protect  the  friction  if 
the  next  size  larger  pipe  of  commercial  rating  be  used. 

There  are  almost  as  many  combinations  of  pipe  sizes 
available  for  hot  water  as  we  found  for  steam  and  they 
are  each  governed  by  the  same  rule.  The  velocity,  the 
volume,  or  cubic  feet  to  be  moved  in  a  given  time,  the 
heat  given  off  from  one  square  foot  of  heating  surface 
per  hour,  all  enter  into  the  size  of  pipe  to  be  selected. 

316 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

Suppose  we  have  1200  square  feet  of  heating  surface 
in  a  hot  water  job,  and  that  the  average  length  of  the 
return  pipes  above  the  top  of  the  boiler  is  found  to  be 
10  feet.  We  have  a  great  variety  of  pipe-sizes  that  can 
be  used,  any  one  of  which  will  be  correct  for  certain 
conditions.  It  is  the  duty  of  the  fitter  to  decide  upon 
the  condition,  and  then  to  have  the  knowledge  and  under- 
standing to  comply  with  the  selected  condition  in  the 
size  of  pipe  used. 

The  most  of  the  open  tank  water  jobs  are  figured  for 
pipe-size  on  the  assumption  that  the  emitted  heat  from 
the  radiator  will  reduce  the  temperature  of  the  water 
in  passing  through  the  radiator  about  10  degrees  and 
that  the  average  height  of  the  return  piping  will  be  10 
feet.  Some  authorities  use  a  loss  of  8  degrees,  others 
figure  the  loss  at  12  degrees  and,  of  course,  each  has  a 
different  set  of  pipe-sizes  from  the  other,  just  as  we 
found  to  be  true  in  steam  heating. 

With  1200  square  feet  of  radiation  surface  and  the 
water  to  be  figured  at  170  degrees  average  in  the  radia- 
tors, we  would  first  note  from  Table  N  Z  that  each  square 
foot  of  surface  required  for  a  drop  of  10  deg.  0.246  cubic 
feet,  then  1200  sq.  ft.  will  require  295.200  (1200X0.246). 
From  Table  M  Z  we  note  that  the  velocity  with  a  drop 
of  10  degrees  is  3744  ft.  per  hour,  so  we  divide  the  total 
cubic  feet  of  water  required  by  the  total  velocity  to  find 
the  area  that  will  be  required  295.200-^-3744=0.078.  As 
there  are  144  square  inches  in  one  square  foot  we  mul- 
tiply 0.078  by  144  and  find  the  area  required,  without 
provision  for  friction,  to  be  11,23  square  inches.  The 
nearest  commercial  size  pipe  larger  is  that  of  a  4-in. 
pipe.  If  we  use  a  loss  of  5  degrees  we  will  find  we  must 
use  a  6-in.  pipe.  If  we  use  a  drop  of  7  degrees  in  pass- 
ing through  the  radiator,  a  5-in.  pipe,  and  so  on  through 

317 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

a  long  list.  It  seems  useless  to  attempt  to  furnish  a  gen- 
eral set  of  pipe-sizes  for  hot  water,  as  every  job  should 
be  figured  for  its  individual  condition.  I  have  clearly 
shown  how  to  do  the  figuring.  It  is  better  that  each  fit- 
ter make  his  list  for  his  locality. 

From  this  table  it  is  evident  that  a  radiator  that  is  20 
ft.  higher  than  the  boiler  will  circulate  more  water 
through  it  than  one  that  is  5  ft.  above  the  boiler,  if  fed 
from  the  same  size  of  pipe.  If  the  water  in  its  passage 
through  the  radiator  at  each  height  delivers  the  same 
relative  proportion  of  heat  per  sq.  ft.  per  Ib.  of  water 
passing  through  it,  it  is  clear  that  a  smaller  pipe  which 
will  deliver  a  less  number  of  pounds  of  water  per  min- 
ute or  hour  to  the  upper  radiator  should  be  used. 

Perhaps  this  increased  velocity  of  the  water  in  sections 
of  a  heating-system  will  be  more  clearly  understood  from 
an  illustration  and  drawing.  The  experience  and  obser- 
vation of  any  mature  person  entitles  him  to  know  that 
a  weight  falling  through  space  increases  its  velocity  as  it 
descends.  The  longer  the  fall  the  greater  the  velocity 
attained.  Water  in  the  pipes  of -a  heating-apparatus  is 
no  exception  to  the  law. 

In  Fig.  28  the  fall  from  the  radiator  1  is  comparatively 
slow  because  of  the  short  distance  that  the  return  water 
has  to  fall.  In  radiator  2,  the  supply-pipe  is  of  the  same 
height,  but  the  drop  is  three  times  as  long  for  the  return 
water  and  therefore  the  movement  will  be  quicker.  In 
hot-water  heating  it  is  the  velocity  of  the  movement  of 
the  return  water  that  determines  the  speed  of  the  circula- 
tion. Neglect  of  this  fact  on  the  part  of  fitters  often 
creates  a  condition  where  the  movement  of  the  water 
almost  ceases. 

Bear  in  mind  that  the  average  radiator  holds  about  1 

318 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 


Ib.  of  water  to  the  sq.  ft.  of  surface,  and  that  while  the 
total  loss  of  heat  between  the  first  supply  and  the  re- 


WflTBK 


THROUGH  RMMOR 
—^  /80\ 


/WATER  COOLEP  /0° 
(  PASSING  Thf?OV6H 
VRGD/ftTOR 


170 


_/7</ 


Fig.  28. 


turn  end  of  the  piping  from  all  causes  may  be  as  much 
as  20  deg.,  the  average  difference  between  the  supply 


319 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

end  and  return  end  of  a  radiator  is  seldom  over  from  5 
deg.  to  10  deg.  This  fact  calls  for  the  exercise  of  some 
judgment  on  the  part  of  the  fitter  when  locating  the  radi- 
ators on  a  job.  A  radiator  near  to  the  boiler,  with  a 
long  drop  to  the  return,  if  fed  full  would  circulate  so  fast 
that  the  difference  between  supply  and  return  would  be 
so  slight,  even  in  a  very  large  radiator,  that  it  could  be 
safely  figured  to  give  off  170  B.  t.  u.  per  hour  per  sq.  ft. 
of  3-col.  surface,  when  the  same  radiator  located  just  as 
near  the  boiler,  so  far  as  its  supply  pipe  was  concerned, 
but  with  the  return-pipe  only  3  or  4  ft.  from  the  level  of 
the  top  of  the  boiler,  would  have  a  circulation  so  slow 
that  140  B.  t.  u.  per  hour  per  sq.  ft.  might  be  all  it 
would  emit. 

It  is  doubtful  if  for  house  work  there  is  at  this  time 
anything  known  for  artificial  heating  that  is  the  equal 
of  hot-water  arranged  to  work  evenly  at  an  average  tem- 
perature of  about  150  deg.  in  the  radiators,  when  it  is  70 
deg.  in  the  room  and  zero  out  of  doors. 


SECTION  XLIV. 


On  some  pipe-lines  a  deficiency  in  the  length  of  drop 
at  the  radiators  the  farthest  from  the  boiler  causes  a 
very  slow  and  unsatisfactory  circulation.  The  remedy  is 
evident.  While  the  demands  for  accuracy  are  greater  in 
the  erection  of  the  hot-water  system  than  in  the  gravity 
steam,  there  are  many  things  about  the  water-heating 
that  appeal  with  commanding  force  to  the  home-owner. 
Now  that  steam-heating  is  practical  at  below  atmospheric 
pressure,  so  that  the  temperature  of  the  radiators  is  no 
greater  than  in  hot-water  heating,  with  the  fuel  expense 
even  less  than  with  most  hot-water  systems,  the  hot- 
water  heating  men  will  either  have  to  learn  to  do  better 
and  much  more  careful  work  when  installing  open-tank 
water-heating,  or  find  themselves  slowly  pushed  out  of 
the  race. 

In  piping  for  the  expansion-tank  there  is  a  great  differ- 
ence in  the  practice  in  different  sections  of  the  country. 
Personally  I  would  advise  that  the  bottom  of  the  expan- 
sion-tank never  be  less  than  30  in.  above  the  top  of  the 
highest  radiator,  and,  when  practical  to  do  so,  I  should 
connect  the  tank  as  shown  on  Fig.  27.  The  higher  the 
expansion-tank  above  the  highest  radiator  the  better.  If 
a  water- job  is  to  be  sealed,  and  a  safety  valve  attached 
to  the  tank,  the  utmost  care  must  be  taken  to  provide 
sufficient  space  in  the  tank  that  there  may  be  a  generous 
air-cushion  in  the  top  of  the  tank.  This  air-cushion  should 
equal  about  one-half  of  the  total  inside  capacity  of  the 
tank  when  the  water  has  attained  its  normal  expansion 
for  the  pressure  it  is  intended  to  carry. 

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A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

In  selecting  a  boiler  for  any  sealed  job,  the  manufac- 
turer should  be  told  that  the  boiler  is  to  be  so  used  and 
a  certificate  of  hydraulic  test  to  at  least  200  Ib.  per  sq. 
in.  should  be  furnished.  This  pressure  is  not  above  that 
at  which  many  boilers  are  regularly  tested,  but  it  is  well 
to  have  a  certificate  of  inspection  and  test  from  the  boiler 
manufacturer  even  when  the  job  is  to  be  sealed  to  the 
extent  of  the  10  Ib.  that  the  majority  of  the  patent-seals 
claim  to  give.  When  the  patent-seal  is  attached  to  the 
return-pipe  near  the  boiler  in  the  cellar  with  a  direct  con- 
nection from  the  top  of  the  seal  to  the  expansion-tank 
in  the  attic,  the  fitter  should  always  request  that  the 
manufacturer  of  the  boiler  he  intends  to  use  should  spe- 
cially test  it  to  200  Ib.  per  sq.  in.  and  furnish  a  written 
certificate  to  that  effect.  The  total  seal  when  set  in  this 
way  is  sometimes  very  heavy,  and  it  is  but  fair  that  the 
manufacturer  of  the  boiler  to  be  used  on  the  system 
should  know  that  a  pressure  in  excess  of  the  open-tank 
system  is  to  be  used. 

In  piping  for  the  sealed  system,  the  same  question  in 
regard  to  the  number  of  pounds  of  water  at  the  higher 
temperature  that  must  be  used  comes  up  for  solution. 
The  velocity  of  the  water  in  a  system  sealed  to  10  Ib.  will 
be  much  more  rapid  than  in  the  open-tank  system,  and 
if  sealed  to  25  Ib.  will  be  more  rapid  than  at  10  Ib.  These 
differences  can  be  stated  in  this  way:  If  in  an  open- 
tank  system,  a  1-in.  pipe  will  supply  40  sq.  ft.  of  hot- 
water  radiators,  the  same  pipe  will  supply  60  sq.  ft.  with 
all  other  pipes  properly  proportioned  to  a  10-lb.  seal,  or 
from  112  to  125  sq.  ft.  and  under  some  conditions  as 
much  as  200  sq.  ft.  can  be  successfully  filled  from  an 
inch  pipe  when  the  seal  is  at  25  Ib. 

Whatever  the  pressure  carried  on  a  hot-water  job,  one 

322 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

stubborn  fact  is  always  present.  To  secure  the  delivery 
of  1  B.  t.  u.  from  a  square  foot  of  radiating  surface  1  lb. 
of  water  must  be  cooled  1  deg.  Fahr.,  and  therefore  the 
number  of  times  the  water  must  pass  through  a  given 
radiator  in  a  given  time  will  be  conditional  upon  the  num- 
ber of  degrees  of  loss  there  is  in  the  temperature  at  each 
passage. 

The  usual  loss  when  the  open-tank  system  is  properly 
proportioned  and  under  average  conditions  is  about  5  deg. 
when  the  water  enters  the  radiator  at  180  deg.  and  the 
air  of  the  room  surrounding  it  is  at  70  deg.  This  is  a. 
higher  temperature  than  is  usual  for  the  average  in  an 
open-tank  system,  but  might  be  secured.  Taking  the 
average  jobs  the  country  over,  and  the  difference  is  per- 
haps 10  deg.,  which,  of  course,  means  a  slower  circula- 
tion. The  average  radiator  will  hold  just  about  1  lb.  of 
water  to  the  sq.  ft.  of  rated  surface,  that  is  the  2  and 
3-column  goods,  and  their  capacity  for  radiating  heat  is 
approximately  1.5  B.  t.  u.  per  degree  of  difference  per 
hour  below  170  deg.,  or  1.6  above  180  deg.  See  Table 
FF,  Section  V.  With  the  average  temperature  of  the 
water  passing  through  the  radiator  at  170  deg.  and  the 
temperature  of  the  room  at  70  deg.,  the  difference  is  100 
deg. ;  this  multiplied  by  the  1.5  equals  150  B.  t.  u.  per 
hour.  If  there  is  the  cooling  of  5  deg.  from  1  sq.  ft.  in 
the  one  circuit  through  the  radiator,  each  pound  of  water 
must  pass  through  the  surface  30  times  in  one  hour.  If 
the  loss  is  10  deg.,  the  circuit  must  be  made  15  times 
per  hour,  and  the  pipe-size  must  be  larger  to  supply  the 
water.  Under  the  conditions  named,  70  cleg,  in  the  room 
and  170  deg.  average  in  the  heating  medium,  it  is  very 
doubtful  if  a  loss  of  over  15  deg.  between  the  entering 
and  leaving  temperatures  is  often  found  in  well-propor- 

323 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

tioned  work.  At  this  point  it  is  well  to  recall  the  fact 
that  with  a  difference  of  15  deg.,  that  with  the  water 
entering  at  170  deg.  and  leaving  at  155  deg.,  the  average 
is  162  deg.,  or  a  loss  in  efficiency  of  nearly  10  per  cent. 
The  difference  wlien  the  water  averages  170  deg.  is  100 
deg.  between  water  and  room,  the  radiator  emitting  150 
B.  t.  u.  per  sq.  ft.  per  hour.  Let  the  water  enter  at  170 
deg.  and  leave  15  deg.  lower,  and  the  average  is  only  162 ; 
the  room  being  at  70  deg.  the  difference  is  92  deg.  and 
the  radiating  value  per  sq  ft.  drops  to  138  B.  t.  u.  per 
sq.  ft.  per  hour  (92X1.5=138).  This  is  a  condition  to 
be  considered  when  the  job  is  being  laid  out  for  the 
workmen. 

The  farther  away  from  the  boiler  the  radiator  receives 
its  supply  of  water,  the  lower  will  be  the  entering  tem- 
perature as  a  rule,  and  also  the  slower  the  natural  circu- 
lation. Fitters  who  use  the  so-called  two-pipe  circuit  and 
who  reduce  the  pipe  every  so  many  hundred  feet  of  radia- 
tor surface,  need  to  be  very  careful,  as  they  near  the  last 
radiator  taken  off,  to  provide  not  only  an  ample  size  in 
the  supply-pipe  but  to  provide  for  a  generous  drop  for 
the  return-pipe. 

Because  of  this  feature  it  will  be  found  in  hot-water 
piping  that  the  overhead  system  is  best  whenever  it  can 
be  used,  as  the  difference  in  temperature  of  the  entering 
water  can  be  more  easily  estimated  and  the  drop  is  cer- 
tain to  be  the  most  rapid  at  the  place  where  it  is  the 
most  needed. 

Next  to  this  come  the  single  main  circuit  in  the  cellar 
with  the  supply-pipe  for  the  radiator  starting  from  the 
side  of  the  main  circuit-pipe  when  near  the  boiler  and 
the  return  entering  the  bottom  of  the  same  circuit-pipe 
farther  along.  As  the  distance  from  the  boiler  increases 

324 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

in  this  sort  of  connection  there  is  no  reduction  in  the 
size  of  the  main-pipe  of  the  circuit  and  as  the  pitch  of 
the  pipe  is  all  the  way  down  from  the  boiler,  the  last 
radiator  taken  off  will  have  a  slightly  increased  drop-pipe 
over  the  next  preceding  radiator  on  the  same  floor.  After 
getting  some  distance  from  boiler  the  radiator  supply- 
pipe  is  taken  from  top  of  main.  There  is  one  other  im- 
portant feature  to  the  credit  of  this  single-pipe  main  cir- 
cuit and  that  is  that  all  elements  which  go  to  accelerate 
the  flow  are  united  in  the  one  pipe.  The  circulation  is 
more  positive  than  in  any  other  cellar-circuit  system.  The 
fact  that  this  type  of  piping  provides  a  continual  circula- 
tion of  the  water  in  the  cellar-pipes  if  every  radiator  on 
the  job  is  shut  off,  is  of  as  much  value  in  this  construc- 
tion as  in  the  overhead  system.  Some  fitters  claim  that 
the  circulation  is  the  quicker  in  the  cellar  single-pipe  be- 
cause it  averages  to  require  less  feet  of  pipe  in  the  total, 
and  therefore  less  friction. 

From  what  has  been  developed  in  regard  to  hot-water 
heating  it  is  evident  that  there  is  always,  even  in  the 
so-called  non-pressure,  or  open-tank  system,  a  greater 
pressure  to  the  sq.  in.  in  the  hot-water  boiler  than  exists 
at  the  steam  boiler  under  present  ratings.  When  the  ex- 
pansion-tank is  several  feet  above  the  top  of  the  highest 
radiator,  say  10  ft.,  and  tank  connection  is  made  to  the 
return-pipe  of  this  radiator,  there  will  be  over  4-lb.  pres- 
sure on  the  circulating  water  at  the  point  where  the  tank- 
connection  is  made.  The  difference  between  the  steam 
gravity  job  at  2  Ib.  at  the  boiler  and  the  usual  hot-water 
job  so  far  as  pressure  on  the  crown-sheet  of  the  boiler 
is  concerned  is  all  in  favor  of  the  steam. 

In  the  matter  of  selecting  the  boiler  for  the  hot-water 
system  all  the  things  that  enter  into  the  question  of  se- 

325 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

lection  for  steam  enter  into  the  careful  selection  for  water 
heating,  namely:  The  size  of  the  fire-pot  (see  section  34). 
The  kind  of  coal  to  be  used  (see  section  28).  The 
number  of  hours  to  be  run  with  one  firing  (see  sec- 
tion 25).  The  division  of  the  fire-surface  (see  sections 
33,  34,  35).  The  stack  temperature  required  to  produce 
the  rating,  is  of  even  greater  importance  to  the  man  who 
is  to  select  a  water-boiler  than  it  is  to  the  steam-fitter 
(see  section  25.) 

The  manner  of  selecting  a  hot-water  boiler  from  the 
B.  t.  u.  transmitted  is  in  no  manner  different  than  with 
the  steam-boiler.  The  only  difference  is  in  the  divisor. 
With  steam  there  is  a  tacit  agreement  on  the  part  of  the 
manufacturers  to  consider  240  B.  t.  u.  per  sq.  ft.  per 
hour  as  the  value  of  radiation,  but  it  is  different  with 
water,  and  it  may  be  found  that  the  majority  of  the  manu- 
facturers are  still  rating  their  boilers  on  the  percentage 
basis,  65  per  cent  more  for  water  than  their  steam-rating 
for  a  given  bo'iler.  It  will  be  necessary,  then,  for  the  hot- 
water  fitter  to  exercise  the  responsibility  that  the  manu- 
facturer has  so  freely  thrown  upon  him  and  select  a 
radiator  value  to  please  himself. 

We  will  assume  that  the  fitter  is  not  desirous  of  wild- 
cat fame,  but  wishes  to  give  his  client  the  safest,  easiest 
to  handle  and  most  economical  sort  of  a  heating  job. 

This  would  mean  that  a  room  temperature  of  70  deg. 
is  to  be  secured  at  zero  weather  with  the  average  tem- 
perature of  the  water  flowing  through  the  pipes  at  from 
150  to  160  deg.,  the  difference  being  only  80  or  90  deg. 
As  the  radiator  has  a  heating  value  of  1.5  B.  t.  u.  per  deg. 
of  difference,  the  divisor  would  be  either  120  or  135  B. 
t.  u.  in  the  place  of  the  240  B.  t.  u.  used  for  steam.  (150 
—70  or  160—70X1-5=120  or  135). 

326 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

In  case  of  closeness  on  the  part  of  owner,  perhaps  one 
of  the  kind  that  stands  up  very  straight  and  declares  "that 
the  man  who  puts  in  the  lowest  bid  and  will  warrant  the 
job  to  heat  will  get  the  contract,"  the  fitter  who  is  so 
crazy  to  get  a  job  that  he  will  put  in  a  bid  for  such  an 
undertaking,  might  figure  to  get  the  expansion-tank  10 
or  15  ft.  above  the  top  of  the  highest  radiator,  and  to 
connect  it  with  the  return  close  to  the  boiler,  and  the 
pressure  thus  attained  will  enable  him  to  figure  safely 
that  the  average  temperature  in  the  radiators  will  be  210 
to  215  deg.  Suppose  he  takes  210,  the  room  at  70,  differ- 
ence 140;  140X1.5=210  B.  t.  u.  for  his  divisor.  In  the 
same  manner  if  he  desired  to  seal  the  job  either  with 
one  of  the  patent  "heat-generators"  or  with  one  of  his 
own,  he  would  decide  as  to  the  temperature  that  the  pro- 
posed seal  would  permit,  from  this  deduct  the  room  tem- 
perature, and  multiply  the  sum  thus  found  by  the  radia- 
tor value  of  1.5  to  1.6  to  find  the  B.  t.  u.  which  each  sq.  ft. 
of  radiator  will  emit,  and  this  will  be  the  divisor  instead 
of  240,  as  for  steam. 

Nearly  every  day  some  honest  well-meaning  fitter  loses 
a  job  to  some  house-wrecking  concern  which  apparently 
undersells  him.  It  is  usually  because  the  fitter,  knowing 
only  one  way  to  figure  a  hot-water  job,  neglects  to  find 
out  that  a  wrought-iron  shell,  made  to  stand  the  pressure 
that  some  high-sounding  named  seal  will  put  on  the  job, 
is  to  be  used  for  the  wildcat  boiler,  and  that  the  piping 
can,  from  its  size,  only  deliver  sufficient  water  to  the  radi- 
ators BECAUSE  of  this  pressure,  which  must  produce  quick 
circulation.  After  it  is  too  late,  he  wakes  up  to  the  fact 
that  he  could  have  sold  what  the  customer  actually  bought 
at  the  same  price  and  have  made  a  bigger  percentage  than 

327 


A    Practical    Manual    of    Steam    and    Hot- Water    Heating 

he  ever  dared  to  put  on  a  legitimate  open-tank  system 
of  the  only  kind  he  knew  anything  about. 

If  the  fitter  desires  to  test  the  rating  of  any  hot-water 
boiler  on  the  basis  of  180  deg.  at  the  boiler,  he  will  con- 
sider the  average  temperature  as  170  deg.  for  the  flowing- 
water,  which  gives  him  just  100  deg.  difference,  and  a 
divisor  of  150  B.  t.  u. 


328 


SECTION  XLV. 


This  leads  us  to  the  matter  of  radiators.  The  first 
radiators  were  crude  indeed.  Of  course  the  first 
radiating  surface  was  pipe  coils  of  1-in.  pipe.  Much 
of  the  confusion  in  the  trade  today  in  regard  to  radiator 
ratings  has  developed  from  lack  of  information  in  regard 
to  the  early  history  of  the  heating-business  and  of  radi- 
ators in  particular.  The  first  recorded  patent  for  a  heat- 
ing-radiator accompanied  with  a  description  that  is  now 
available,  was  granted  to  Anthony  Hitchings  in  1848. 
There  was  a  patent  granted  12  or  13  years  before  this  to 
Robert  Rogers  of  South  Berwick,  Me.,  but  all  trace  of 
what  form  his  system  of  steam-heating  assumed  was 
destroyed  by  the  Patent  Office  fire  of  1836. 

The  illustration,  Fig.  29,  of  the  original  Gold  boiler,  as 
produced  by  H.  B.  Smith  &  Co.,  is  very  interesting,  in 
that  it  shows  that  Gold's  idea  in  the  first  place  was  not  to 
use  the  header  and  return,  or  mud-drums,  but  to  provide 
for  an  internal  circulation. 

It  is  probable  that  the  troubles  that  come  to  the  manu- 
facturers because  of  the  difficulties  of  maintaining  tight 
joints  with  the  rubber  gaskets,  when  the  boilers  were  used 
at  the  high  pressure  used  in  those  days,  led  to  the  pro- 
duction of  the  header  and  return-drums  in  order  that  a 
screw-nipple  construction  might  be  employed  and  thus 
get  rid  of  the  troublesome  rubber  gasket. 

This  connection  became  practically  universal;  and  as 
years  of  use  accustomed  the  fitters  to  this  header-connec- 
tion, in  time  many  of  them  came  to  think  that  there  was 
something  of  special  circulating  merit  in  the  device. 

320 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 


That,  with  the  improved  mechanical  facilities  of  the 
present  day,  manufacturers  should  go  back  to  the  original 
Gold  idea  of  an  internal  circulation  without  the  use  of 
the  cumbersome  outside  connection,  is  a  striking  proof  of 
the  vitality  and  correctness  of  Samuel  Gold's  original  idea 
as  to  the  proper  construction  of  a  cast-iron  heating- 
boiler. 

Fig.  30  will  be  interesting  as  showing  the  first  Amer- 
ican patent  for  a  system  of  hot-water  heating.  The  chief 


CONNECTtOH  BOLT 


COfiL  GROTE 
LONG  BOLT 
FUBBBR 


ASH 


ASH  6rRAT£  POOR 
ASH   PIT  POOR 


Fig.  29. 


feature  of  the  outcome  of  Hitching's  patent  seems  to  have 
been  that  it  compelled  fitters  to  use  pipe  for  radiating  the 
heat  in  steam  and  water-heating  systems,  or  buy  of  Hitch- 
ings. 

In  order  that  the  manner  of  rating  radiators  shall  be 
clearly  understoood.  it  will  be  necessary  to  trace,  very 

330 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

briefly,  the  evolution  of  pipe-coils  into  pipe-radiators  and 
the  rise  of  the  cast-iron  radiator  as  a  competitor. 

It  would  undoubtedly  be  interesting  to  many  to  have 
the  whole  history  given,  but  to  do  that  would  be  to  write 
a  book.  I  personally  believe  that  such  a  book  from  a 


HATER 


BALL  COCK 


A- 

B- 


Svmr 
p/fe  F 


P      \00X 


& 

RtttKW* 


A  r  OUTER  P/PE   /#    M/CH 


WHICH 


ro 

Fig.  30. 

competent  writer  would  be  of  great  interest  and  value 
to  the  trade  and  the  public. 

The  first  radiating  surface  used  was  mostly  of  cast-iron 
pipe.  A  little  later  gun-barrels  were  used  for  this  pur- 
pose to  such  an  extent  that  the  secretary  of  the  United 
States  treasury  called  attention  to  it  in  one  of  his  reports 

331 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

to  congress,  in  which  he  mentioned  the  beginning  of  a 
wrought-pipe  industry  in  this  country. 

The  first  variation  from  a  single  pipe  around  the  wall 
was  what  was  called  the  "flat-coil."  This  was  either  pipe 
or  gun-barrels  from  30  to  48  in.  long,  screwed  into  return- 
bends.  This  was  followed  by  what  was  known  as  "two- 
section  coils,"  which  were  simply  two  "flat-coils"  fastened 
up  side  by  side  with  a  "chuck-spacer"  to  fix  the  distance 
between  them.  Following  this  came  what  were  known 
as  "manifold-coils,"  the  pipes  being  3  or  4  pipes  wide. 
The  "box-coil"  came  into  use  for  indirect  work,  taking 
its  name  because  it  was  boxed  close  into  its  place  in  the 
cellar.  There  were  several  other  designs  of  pipe-con- 
struction which  were  used  in  a  horizontal  position,  and 
the  name  for  which  was  as  significant  to  the  trade  as  the 
"box-coil,"  and  about  as  unintelligible  to  the  fitter  of  to- 
day ;  as,  for  instance,  the  difference  between  a  "flat-coil" 
and  a  "wall-coil,"  although  there  was  a  marked  difference. 

The  fitters  of  those  days  made  many  attempts  between 
1848  and  1862  to  produce  vertical  radiators  from  pipe, 
but  with  slight  success,  and  it  was  not  until  1862  that  the 
problem  was  solved. 

In  March,  1863,  there  was  issued  to  Mason  and  Briggs 
a  patent  for  a  steam  radiator  composed  of  vertical  tubes 
screwed  into  a  horizontal  cast-iron  base,  the  tubes  having 
an  inner-tube,  or  a  diaphragm,  which  served  to  prevent 
the  steam  from  compressing  the  air  and  thus  preventing 
the  circulation  of  either  the  steam  or  the  air.  It  is  rather 
curious  to  find  these  two  greatest  of  American  steam-en- 
gineers adopting  for  the  first  successful  vertical-pipe  radi- 
ator the  inner  tube  shown  in  the  patent  granted  to  Hitch- 
ings  in  1848  for  a  hot-water  radiator.  It  is  also  notable 
that  while  Hitchings'  patent  did  not  expire  until  1865,  or 

'332 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

for  three  years,  that  Nason  and  Briggs  considered  Hitch- 
ings  could  use  his  radiator  as  a  steam-radiator. 

Within  the  few  years  immediately  following  1862,  the 
Walworth  radiator  and  one  or  two  other  pipe-radiators 
received  Patent-Office  protection  because  of  some  novelty 
in  the  manner  of  construction. 

In  this  way,  from  1862  to  1879,  the  vertical-pipe 
wrought-iron  radiator  business  fell  into  the  hands  of  con- 
cerns of  great  capital  and  great  business  ability.  These 
were  the  men  who  had  the  inventive  power  and  the  busi- 
ness capacity  to  make  the  steam-heating  development  in 
this  country  in  those  17  years  one  of  the  business  marvels 
of  the  19th  century.  After  the  close  of  the  Civil  War 
the  heating-business  began  to  attrract  the  attention  of  the 
manufacturers  of  cast-iron. 

Nason  and  Briggs,  in  putting  their  radiator  on  the 
market,  arranged  its  surface  in  such  manner  that  each 
wrought-iron  pipe  and  its  proportionate  part  of  the  cast- 
iron  base  and  top  should  present  exactly  one  sq.  ft.  of 
surface  to  the  air. 

Their  first  patterns  were  for  single-pipes  only,  and 
about  30  in.  in  height.  The  demand  for  less  extended 
radiators,  when  quite  large  surfaces  were  required,  led 
to  the  making  of  2-section,  and  later  to  3  and  4-section 
radiators.  But  each  section  was  figured  to  present  exactly 
one  sq.  ft.  of  surface.  Do  not  overlook  the  supreme  im- 
portance of  this  fact.  It  is  the  key  that  will  unlock  for 
us  the  methods  adopted  by  the  cast-iron  men  when  they 
got  into  the  radiator  game. 

The  production  of  radiator  surface  in  absolute  units 
of  one  sq.  ft.  immediately  led  to  the  adoption  of  the  fol- 
lowing method  in  ordering  radiators.  Suppose  a  fitter 
wanted  24  sq.  ft.  of  surface  in  each  of  four  radiators,  and 

383 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

sent  in  an  order  for  four  standard  height  steam  radiators, 
one  1x24,  one  2x12  one  3x8  and  one  4x6.  There  would 
be  shipped  to  him  four  radiators,  each  of  which  actually 
contained  24  sq.  ft.  of  heating-surface,  but  he  would 
very  soon  find  out  that  the  1x24  would  heat  more  air 
than  the  2x12,  and  that  would  heat  the  same  amount  of 
air  hotter  than  the  3x8,  and  that  in  turn  more  than  the 
4x6.  In  this  respect  there  was  no  difference  between  the 
vertical  pipes  "bunched"  and  the  "wall-coils"  'bunched." 
The  usual  howl  of  "overrated"  went  up  from  those  fitters 
who  were  so  "practical"  that  they  never  needed  to  study 
or  even  read  the  "fool  stuff  that  the  book  men  get  out." 

Mr.  Nason  gave  out  the  results  of  a  few  tests  made  by 
him  as  follows:  From  single  horizontal  1-in.  pipe,  64 
ft.  in  length,  and  filled  with  steam  at  228  deg.  tempera- 
ture, the  air  in  the  room  being  at  70  deg.,  he  found  the 
pipe  emitted  447  B.  t.  u.  per  sq.  ft.  per  hour.  His  test 
on  a  1x24  Nason  and  Briggs  wrought-iron  radiator 
showed  that  under  the  same  conditions  the  value  was  390 
B.  t.  u.  per  sq.  ft.  per  hour.  Under  the  same  conditions 
he  found  that  a  2x24  Nason  and  Briggs  radiator  only 
emitted  309  B.  t.  u.  per  sq.  ft.  per  hour,  and  a  3x16 
emitted  at  the  rate  of  278  B.  t.  u.  per  sq.  ft.  per  hour. 
Mr.  Nason  endeavored  to  make  it  clear  to  those  who 
wished  to  know  that  there  was  a  material  difference  in 
the  heating-value  of  24  sq.  ft.  of  1-in.  pipe  surface  as  a 
radiator  of  heat,  caused  by  the  position  in  which  it  was 
placed,  horizontal  or  vertical,  and,  again,  it  made  a 
more  pronounced  difference  if  the  surface  was  massed 
in  close  parallel  rows. 

As  the  result  of  the  discussion  at  that  time,  different 
wrought-iron  radiator  manufacturers  produced  radiators 
which  they  warranted  to  contain  1  sq.  ft.  to  each  pipe, 

334 


A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

but  some  there  were  who  endeavored  to  furnish  for  each 
single  section  of  pipe,  cast-iron  base  and  top,  which  con- 
stituted- the  radiator,  enough  additional  surface  beyond 
that  in  the  Nason  and  Briggs  wrought-iron  radiator  so 
that  a  1x24  section,  for  intance  should  emit  447  B.  t.  u. 
per  sq.  ft.  per  hour  under  standard  conditions  as  they 
then  existed.  This  had  the  effect  of  making  these  radi- 
ators more  than  30  in.  high. 

After  the  close  of  the  war  between  the  states,  the 
possibilities  of  the  heating-business  began  to  impress  it- 
self on  the  foundrymen  of  the  east.  They  very  soon  be- 
came a  factor  of  importance  in  the  boiler  part  of  the 
trade,  but  in  order  to  get  the  radiator  business  into 
their  hands  something  would  have  to  be  originated  that 
could  compete  with  the  wrought-iron  radiators  in  effi- 
ciency, appearance,  and  durability. 

The  popular  width  in  the  wrought-iron  radiator  was 
the  2-column.  The  first  cast-iron  radiator  to  catch  the 
popular  fancy  was  the  "Bundy"  radiator.  This  was 
brought  out  in  1869  and  was  the  invention  of  Nelson  H. 
Bundy,  of  the  firm  of  Bundy  &  Healy,  of  New  York. 
With  some  minor  changes  from  the  original  "Bundy" 
the  radiators  manufactured  by  the  late  A.  A.  Griffing 
Company  of  Jersey  City,  N.  J.,  was  the  same  as  this  first 
real  competitor  of  the  wrought-iron  radiators.  The  orig- 
inal patterns  of  the  "Bundy"  are  owned  now,  and  have 
been  for  many  years,  by  the  Walker  &  Pratt  Mfg.  Co., 
of  Boston,  Mass. 

In  order  to  secure  the  same  number  of  heat-units  per 
sq.  ft.  rated  surface  in  a  2-col.  cast-iron  radiator  that 
would  be  emitted  from  some  larger  unit  in  the  2-col. 
wrought-iron  radiator,  it  was  found  that  by  making  the 
cast-iron  radiator  a  little  higher,  each  section  could  be 

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A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

made  to  have  the  same  value  in  B.  t.  u.  emitted  as  a  2x2 
wrought-iron  standard  radiator  of  the  Nason  and  Briggs 
type. 

This  fixed  the  standard  for  2-col.  cast-iron  radiators 
as  4  sq.  ft.  per  section,  and  height  would  vary  according 
to  width.  When  in  the  course  of  time  other  foundrymen 
dipped  into  the  making  of  radiators,  they  followed  the 
precedent  of  the  "Bundy"  and  professed  to  make  their 
2-col.  radiators  to  emit  the  same  number  of  heat-units 
per  section  as  a  2x2  wrought-iron  pipe-radiator  of  the 
standard  of  the  Nason  and  Briggs  type,  and  as  a  result 
2-col.  cast-iron  radiators,  rated  at  4  sq.  ft.  per  section, 
ranged  from  34  to  39  in.  in  height. 

The  growth  of  the  radiator  business  among  the  foun- 
drymen soon  led  them  to  produce  3  and  4-col.  radiators. 
It  is  at  this  point  that  the  confusion  arises  in  the  minds 
of  those  who  are  not  conversant  with  the  methods  which 
the  cast-iron  men  used  in  rating  their  goods.  When  the 
matter  of  rating  the  3  and  4-col.  cast-iron  radiators  came 
up,  they  were  fashioned  so  that  each  section  should  emit 
a  certain  number  of  heat-units  relative  to  the  wrought- 
iron  goods  of  a  3  or  4-col.  That  is,  one  section  of  the 
cast-iron  radiator  should  equal  a  definite  number  of  sec- 
tions of  "bunched"  wrought-iron  pipe  sections.  The  3- 
col.  radiator  proved  to  be  a  troublesome  proposition.  In 
order  to  get  the  efficiency  of  6  Nason  pipes  in  a  casting 
of  the  same  height  that  had  been  established  for  2-col. 
cast-iron  radiators  of  4  sq.  ft.  to  the  section,  a  radiator 
of  undue  width  presented  itself.  It  was  thought  that  the 
height  had  already  been  raised  as  much  as  the  public 
would  stand,  and  finally  the  matter  was  solved  by  taking 
a  3x5  wrought-iron  radiator  containing  15  sq.  ft.  as  the 
standard  from  which  to  create  the  competing  cast-iron 

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A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

sections.  In  this  way  it  became  possible  to  produce  a  3- 
col.  cast-iron  radiator  that  would  emit  under  the  then 
standard  conditions  of  steam  in  radiator  at  228  deg.,  air 
in  room  at  70  deg.,  4,170  B.  t.  u.  for  15  ft.  of  the  massed 
or  bunched  surface,  this  being  the  same  that  a  3x5,  or  15 
sq.  ft.  of  3-col.  wrought-iron  pipe  radiator  emitted  under 
same  condition,  viz. :  278  B.  t.  u.  per  sq.  ft.  of  surface 
at  temperature  difference  of  158  deg. 

Probably  there  has  been  more  notice  taken  of  the  size 
of  the  cast-iron  4-col.  radiator  in  connection  with  its  rat- 
ing of  8  sq.  ft.  than  of  any  other  pattern.  To  most  of  the 
trade  this  8-ft.  rating  has  seemed  like  highway  robbery. 
But  when  measured  against  a  4-col.  pipe  mass,  it  is  the 
one  pattern  of  all  the  cast-iron  goods  that  is  the  most 
conservatively  rated. 

The  great  trouble  with  the  cast-iron  radiator  proposi- 
tion is  that  the  trade  has  been  fooled  into  buying  the 
goods  by  the  square  foot  of  alleged  surface,  instead  of 
buying  what  they  themselves  are  called  upon  to  sell, 
British  thermal  units  of  heat.  When  the  trade  gets 
around  to  the  point  of  vantage  which  enables  them  to 
buy  radiators  on  the  basis  of  the  number  of  heat-units 
given  off  under  the  new  standard  conditions,  imposed  by 
the  new  rating  placed  upon  boilers,  instead  of  buying  sc 
many  square  feet  of  cast-iron,  trusting  to  luck  and  guess- 
ing that  the  job  will  come  out  all  right,  as  they  now  do, 
they  will  require  of  the  radiator  manufacturer  a  garanteed 
statement  of  the  heat-units  that  each  pattern  of  radiator 
will  emit  when  placed  under  the  standard  conditions  that 
the  manufacturers  themselves  have  created.  And  why 
should  radiators  be  sold  upon  any  other  basis?  It  is 
heat-units  that  you  are  obliged  to  furnish  when  you  con- 
tract to  heat  a  building.  Why  then  should  you  purchase 

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A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

square  feet  of  iron  without  the  slightest  intimation  of  a 
garantee  as  to  its  capacity  for  delivering  the  heat  you 
have  contracted  to  furnish  with  "not  to  exceed  2  Ib.  pres- 
sure at  the  boiler"  for  your  steam  job,  or  with  the  ther- 
mometer not  above  180  deg.  at  the  boiler  in  the  hot- water 
job? 

From  those  who  have  followed  me  from  the  time  we 
commenced  with  the  chimney  to  this  last  question,  I  be- 
lieve that  there  will  be  but  one  reply. 

When  the  steam-fitters,  the  hot-water  fitters,  the  archi- 
tects and  the  engineers  on  whom  the  burden  of  selection 
and  garantee  lias  been  thrown  by  the  manufacturers,  call 
for  heat-unit  values  from  the  manufacturers  as  the  only 
standard  upon  which  business  will  be  done,  scientific  heat- 
ing will  have  commenced. 

To  give  the  common-school  fitters  of  the  country  an 
idea  of  the  fundamental  principles  of  the  science  that  they 
are  practicing  in  their  daily  work,  has  been  my  aim, 
rather  than  to  present  a  series  of  hard  and  fast  rules, 
which,  from  the  very  nature  of  the  heating-problem, 
could  only  serve  to  confuse  those  who  had  some  insight 
into  heating-problems  as  stated  by  others. 

To  furnish  plain,  even  if  at  times  long,  explanations  for 
each  of  the  more  important  items  which  enter  into  the 
design  and  erection  of  a  steam  or  hot-water  heating-ap- 
paratus, to  the  end  that  any  intelligent  workman  may,  by 
the  aid  of  the  tables  and  explanations,  be  able  to  recon- 
cile most,  if  not  all,  of  the  differences  that  the  publishing 
of  numbers  of  individual  rules  has  created,  has  seemed  to 
me  to  be  the  helpful  thing  to  bring  to  the  American  archi- 
tects and  workmen  in  the  steam  and  hot-water  heating 
lines. 

When  these  workmen  have  once  grasped  the  funda- 

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A    Practical    Manual    of    Steam    and    Hot-Water    Heating 

mental  facts  which  govern  the  heating-problems,  it  will 
not  be  necessary  to  furnish  cut  and  dried  rules  for  them. 
They  have  the  capacity  to  work  out,  each  for  himself,  a 
better  working-plan  for  each  individual  contract  than  can 
be  furnished  ready-made. 

To  the  man  who  desires  to  be  reasonably  well  prepared 
to  construct  intelligently  either  steam  or  hot-water  house- 
heating  jobs,  it  is  believed  the  plain  reasons  for  each 
step  which  have  been  detailed  in  the  discussion  here 
ending  will  prove  of  value.  But  sound  common-sense, 
applied  to  each  job  as  it  comes,  is  as  much  needed  as 
the  knowledge  of  rules.  King  David  instructed  Solo- 
mon, whom  we  are  told  became  the  wisest  of  men,  as 
follows : 

"Get  wisdom,  get  understanding.  Forget  it  not.  Wis- 
dom is  the  principal  thing ;  therefore  get  wisdom, 
but  with  all  thy  wisdom  g,et  understanding."  The 
advice  is  said  to  have  worked  out  well  when  ac- 
cepted by  Solomon.  Think  it  over. 


339 


i/r 


24*333 


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